BY THE OPTIMIST DAILY EDITORIAL TEAM
A dam fell in Iceland last December, the first the country has ever deliberately dismantled. The structure on the River Melsá had long since stopped generating power. Sheep were living in the old powerhouse. “It wasn’t providing any electricity,” said Hamish Moir, a river engineer from CBEC, the Scottish firm that provided technical support for the demolition. To see the river restored to its natural state, he said, was “really rewarding.”
That would have been a footnote in a quieter year. Then the European numbers came in.
A record 602 river barriers were removed across the continent in 2025, up 11 percent from the year before, according to a new report from Dam Removal Europe. The removals reconnected 2,324 miles (3,740 kilometers) of rivers, pushing the EU closer to its goal of restoring 15,500 miles of waterways to their natural state by 2030.
A sixfold increase in six years
The pace has accelerated sharply. River barrier removals across Europe have grown sixfold since the first official count in 2020. Iceland and North Macedonia took down barriers for the first time in 2025. Sweden led the continent with 173 removals, followed by Finland with 143 and Spain with 109. The UK removed 35.
More than three-quarters of what came down were structures smaller than about six and a half feet (two meters). Many no longer served any economic function. They were ageing obstacles blocking fish passage and disrupting the sediment flows that riverine ecosystems depend on.
The ecological cost of a fragmented river
Dams and weirs are not neutral infrastructure. They block fish migration, alter water temperature and flow, and prevent sediments from reaching coastal areas downstream. Freshwater migratory fish populations in Europe have declined by 75 percent since 1970, and much of that collapse is attributed to the fragmentation of river systems by barriers.
“For centuries, Europe treated rivers as engines for economic growth, damming them for mills and hydropower, straightening them for navigation, and burying them beneath cities,” said Chris Baker, director of the European branch of Wetlands International. “We built our prosperity by fragmenting our rivers, but the ecological price has been enormous.”
The EU’s nature restoration law, which took effect in 2024, explicitly calls for barrier removal as part of reconnecting rivers and lakes across the continent.
One complication worth watching
Restoring river connectivity is not straightforward. A study published last year found that artificial barriers can also slow the spread of invasive species, creating what researchers call a “connectivity conundrum”: when barriers come down, species previously contained can move into new stretches of river.
“While initial improvements in connectivity can be rapid, stressors such as invasive species can eventually accumulate and erode longer-term conservation value,” said Ellen Dolan, a biologist at Queen’s University Belfast and lead author of the study. Careful preparation, monitoring, and long-term management, she adds, can reduce those risks.
None of this changes the overall picture. More than a million barriers fragment Europe’s waterways, and tens of thousands are thought to be obsolete. Removing them is slow work. Six hundred a year is a start.
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