In the decades following the Second World War, Finland expanded its forestry sector as part of national economic rebuilding. A major national policy involved draining peatlands to support timber production. Across the country, extensive ditch networks were cut to lower water tables and convert wetlands into forest. Although this approach became widespread, it often caused significant ecological damage and in many places did not lead to the intended establishment of forest. Haravasuo, a peatland in the Koitajoki Watershed of Eastern Finland, is one of many examples where the national push to convert peatlands into forest failed and left long lasting environmental impacts.
Trees never established at Haravasuo, and the drainage system remains active more than 70 years later. Water continues to transport phosphorus, mercury, and organic matter from the site into nearby rivers and lakes, affecting water quality downstream in the Koitajoki River.
Peatlands like Haravasuo are important ecosystems. They store carbon, filter water, and support a wide range of species. When drained, they release carbon dioxide and lose these ecological functions. Rewetting is one of the most effective ways to restore their natural role. At Haravasuo, this involves constructing hand-built dams from peat and wood to block the old ditches and raise the water level.
River Guardian Tom Toivonen, who lives near the site, has played a key role in monitoring these interventions and documenting how the landscape is responding. Through regular field visits, drone surveys, and a custom mapping system, he is helping track the progress of restoration.
Tom has been involved in the restoration of Haravasuo since the beginning. He supported the construction of many of the dams now holding back water across the site and has a strong understanding of how each one contributes to the rewetting effort.
Improving monitoring in a challenging landscape
Haravasuo spans several square kilometres and includes dozens of dams built by the Snowchange team and River Guardians. Tom initially inspected them on foot but quickly encountered seasonal limitations. “Without skis, I would sink,” he explained. “It would take several days to inspect all the dams, and in summer it’s impossible.”
There is only a short window in early spring or late autumn when the ground is frozen but not yet snow-covered. To adapt, Tom began using a drone. With two flights – one over the northern area and one over the south – he can now complete a full inspection in under an hour. “Just last week I inspected all the northern dams in 20 minutes,” he said.
A system for clarity and collaboration
As restoration progressed, Tom faced another challenge: how to communicate the precise locations of dams with the wider team. Screenshots and location pins were helpful but not always reliable.
To address this, he developed a structured monitoring system using Google MyMaps. Each dam was assigned a label, and documented with photos and notes.
“The signs I’ve installed on the dams help us identify them from drone photos. If there’s an issue with A12, I can just say that, and everyone knows exactly where I mean,” Tom said.
This approach now provides a reliable and accessible way to monitor dam performance and share information within the team.
A closer look at restoration in action
Tom’s map documents dozens of dams across Haravasuo, each labelled and photographed to help track its condition over time. Three of these stand out as examples of how monitoring is helping shape decisions on the ground.
One of the most frequently inspected is B9, a dam located in a relatively accessible part of the peatland. It has become a reference point for observing how rewetting is progressing. Drone images show water pooling upstream to such an extent that it is evident also in satellite images. These observations confirm that the structure is working as intended to hold water in place and slow its movement through the landscape.
Aerial photos of dam A12 revealed water escaping around the edge of the dam, rather than backing up behind it. “It’s very clear we need to come back in the summertime and fix this leak,” Tom said. Smaller dams next to A12 will help recapture the diverted flow and ensured that the restoration has maximum effect. Additional dams will be built further downstream to ease the pressure on one specific dam.
Then there is A1, a dam built on slightly higher ground. Tom noted that the water level has never reached it. “Eventually one day the water might be this high,” he said, “but I doubt it.” While it currently serves no hydrological function, it remains on the map, labelled and documented, as part of the full record of work done at the site.
Each of these examples illustrates a different aspect of adaptive restoration. Whether functioning well, needing repair, or turning out to be redundant, each dam contributes to the evolving understanding of how the site responds to rewetting and how restoration efforts can be refined along the way.
Sharing results and building a legacy
The MyMaps system not only supports day-to-day work, but also offers a long-term record of change. “I wish we’d started this from the beginning,” Tom said. “We could have documented what each dam looked like before it was built, and then recorded how the landscape changed. I have tried to upload at least one summer and one winter picture of each major dam.”
The map also links with satellite imagery, which is periodically updated by Google. “Twenty years from now, someone could use the same map to see how much the water has spread,” he added.
A practical tool for future projects
Tom believes this system could be useful for other restoration efforts, particularly in remote or seasonally inaccessible areas. By combining visible labels, drone imagery, mapped data, and local knowledge, it offers a practical, low-cost monitoring model that others can replicate.
“It won’t become a lake,” he said, “but it will be a huge, wet swamp again, full of moss and wetland species.”
As the Endangered Landscapes & Seascapes Programme continues to support restoration across Europe, Haravasuo is showing how local commitment and simple tools can help bring degraded ecosystems back to life.
This article was written by Iona Haines, Endangered Landscapes & Seascapes Programme Communications Coordinator. To find out more about the Koitajoki Watershed, visit their project page.
