Only a fraction of Estonian streams and rivers untouched by human activity

Jürgen Karvak, junior researcher in stream ecology at the University of Tartu, noted on the "Ökoskoop" program that it is rare to find a stream or river in Estonia that has remained untouched by human impact in its entirety. Before restoration efforts begin, it is crucial to understand the goals of such an endeavor.
Jürgen Karvak explained that a significant portion of water bodies across Estonia have been reshaped extensively. "We have around a thousand dams that obstruct river flow. At least 40 percent of streams and rivers have been straightened. Straightening involves creating a new bed and usually results in the cutting down of riverside forests, leading to young and species-poor communities," he said.
"Such uniform communities negatively impact the population of all other species," Karvak added.
He outlined four main human-related factors affecting the condition of watercourses: damming, which hinders free flow; drainage and straightening, altering the water regime; changes to riverbanks and surrounding forests; and excessive nutrients and pesticides from fields entering the water. These factors are closely linked and amplify each other's effects.
Of Estonia's thousand dams, 75 percent are impassable to fish. About 40 percent significantly impact the condition of fish populations, benthic fauna and vegetation.
Linnamäe Reservoir needs to be liquidated
Kaili Viilma, head of the nature use department at the Environmental Board, discussed the need to cease damming at Linnamäe to improve the condition of the Jägala River. The Environmental Board's draft regulation, which would end the damming permit at Linnamäe, is open for review until the end of the first decade of May, followed by a public discussion. "We really hope that we can find a compromise for Linnamäe similar to the one for Sindi," said Viilma.
Viilma mentioned that the Environmental Board collaborates with the National Heritage Board. "Sometimes, the natural value outweighs the human-created value, and we need to protect nature for humans as well," she stated.
"As a society, we should learn to set priorities. In Estonia, we have about a thousand dams, a third of which do not have environmental permits and continue to damage the environment. If our actions have caused such poor conditions for species and habitats, we should consider what is more important to us. Therefore, we agree with the court's view that environmental arguments, when justified, outweigh all other arguments emphasizing aesthetics, convenience or the well-being of small interest groups," Viilma explained.
"The Jägala River is unique because it originates from or flows through the limestone bluff and would naturally have rapids. There are a little more than ten such water bodies in Estonia where salmon from the Gulf of Finland spawn, and they are of poor quality. The Jägala River has had nearly 20 percent of the Gulf of Finland's salmon spawning grounds," she clarified.
"Indeed, the court has found that such activities in Natura 2000 areas can only be permitted if they do not harm local natural values," Viilma noted.
Viilma emphasized that three conditions must be met to make exceptions in Natura areas. In addition to an overwhelming public interest, there must be no alternatives to the proposed activity, such as energy production. Additionally, any damage to nature in Natura areas must be adequately compensated. For Linnamäe dam, such a possibility does not exist.
"Linnamäe produces just over 1 megawatts (MW) of energy, while modern onshore wind turbines have a capacity of 6 MW. Thus, the total hydroenergy produced could be covered by a single onshore wind turbine," Viilma added.
Restoration work concerns other rivers and dams
Sander Sandberg, a freshwater ecology specialist at the State Forest Management Center (RMK), noted that in addition to the Jägala River, several other major rivers and dams in Estonia, such as those on the Kunda, Ahja and Elva rivers, remain unresolved. The RMK is currently working on the Pedja and Keila rivers, upstream from the waterfall, in cooperation with the Environmental Board.
"Downstream from the Keila waterfall, the situation is good, with no dams. Upstream, in the middle reaches around Kohila, there are several dam structures. We're not just talking about valuable species targeted by commercial fishermen, but also about protected species that need these migration paths in the river," he commented.
The RMK plans several practical tasks. "Our activities next year will include restoring spawning grounds and different habitat types in rivers. We aim to take a longer and broader view of the river, so we're not just focusing on one spot," he said.
"If we can get fish to migrate over this one point, we must look both upstream and downstream to ensure there are suitable habitats and spawning grounds, and that food is available for these fish. We take a broader approach and try to bring positive changes to the riparian area, providing living and feeding places for various birds and insects," explained Sandberg.
Through the LIFE CleanEST project, efforts are being made to improve the water environment in Ida-Viru County, still affected by last century's oil shale industry pollution. Annabel Runnel, the project manager of the LIFE CleanEST at the Environmental Agency, mentioned that one focus is currently on the Purtse River. According to records, it had 12 dams, with only five remaining today. The largest, Püssi Dam, is impassable to fish. "The design work for the Püssi Dam has been lengthy, but we found that the best solution would be a rapid fish passage," Runnel said.
The project has not faced opposition. "All stakeholders and interest groups have agreed with this better solution for the river. It makes the river more natural while maintaining the damming level," she stated.
"Last year, if Püssi Dam was in an open state, the monitoring results showed that lamprey larvae reached the upper reaches. This shows that habitat quality is still present. Therefore, the Püssi Dam should be permanently removed to ensure free migration," she added.
"Last year, we also dismantled a dam ruin and a larger concrete object on the upper reaches during a volunteer event, which was also a barrier to fish migration," she discussed the work already done.
One area of concern remains industry, such as a planned cellulose factory nearby. "They plan to take water from the Ojamaa River, which also supplies the Purtse with water. However, this used water would be directed back to the sea, not into the Purtse River. Such plans definitely require thorough analysis, as the entire Purtse River downstream from Ojamaa would be affected by this reduction in water. It could also jeopardize our great effort that we have made so far through various projects," she revealed the nature of the problem.
Runnel acknowledged that industry in Ida-Viru County has historically impacted and will continue to affect the rivers. "Both the state and entrepreneurs can contribute to preserving the river as an ecosystem and restoring it from its current pollution," said Runnel.
Restoring watercourses supports diversity on a wider scale
Jürgen Karvak highlighted the rapid restoration potential of watercourses. "It's positive that some of the fauna, like fish, return quite quickly after dam removal. The results of stream restoration can be noticeable rather swiftly, with certain species making a comeback even within a year. However, the development of a more diverse community takes longer," he explained.
Karvak stressed the need for clarity in the overall goals of stream restoration. "Are we restoring a historical state, such as an old riverbed, improving the condition of a particular species or enhancing the functioning of a community so that natural intrinsic processes like water self-purification or food web dynamics can operate?" he asked.
He noted that global expert opinions are leaning towards the goal of restoring natural functions, which would bring about better conditions for living organisms and increase natural diversity.
"When dealing with a straightened river segment, it's not always necessary to re-meander it, as this can be a major disturbance. It's very expensive, and we can only do it for a small stretch of the river," Karvak remarked.
Sometimes, simply adding tree trunks and rocks to the straightened river can suffice. "In some places, we assist a little with an excavator, and the natural river flow starts to restore and heal that section on its own. This way, we can make changes on a much larger scale in the landscape. We need to choose such methods that allow the damaged nature to recover over time on its own," the researcher concluded.

LIFE IP CleanEST is an integrated water management project that is focused on improving the status of water bodies in Ida-Viru and Lääne-Viru Counties. More information is available by clicking these words.
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Editor: Marit Valk, Jaan-Juhan Oidermaa, Marcus Turovski
Source: "Õkoskoop"