Undamming Europe

Europe is on a river-barrier demolition spree—23 countries demolished 542 barriers in 2024. The continent must pursue this trend more vigorously if it is to meet its target of making 25,000 km of rivers barrier-free by 2030.

According to data compiled by Dam Removal Europe (DRE), a coalition of six organisations including the World Wide Fund for Nature (WWF), The Nature Conservancy and the European Rivers Network, Europe has one dam for every kilometre of its rivers. Little wonder, then, that countries are increasingly joining the drive to enable rivers to flow free and to restore original aquatic ecosystems. The number of barriers removed last year was the highest since the drive started in 2020, says DRE data. In 2020, some 11 countries removed 101 barriers like dams, weirs, culverts and sluices on rivers. By 2023, this rose to 15 nations removing 487 barriers.

The drive in Europe is happening in context of global concerns over ecological impacts of increased blocking or damming of rivers. These human-made barriers are one of the earliest interventions that were made in natural ecosystems to harness benefits for people. Their potential impacts are highlighted in the UN Environment Programme's (UNEP's) “Frontiers 2025: The Weight of Time” report, released on July 10. “While dams have provided significant benefits, they have also disrupted indigenous and fishing communities, while damaging river ecosystems,” notes the report, calling for a global effort to let rivers flow free.

Removing dams and barriers is an increasingly accepted strategy to restore river health. It has gained momentum, particularly in Europe and North America, where large, older dams that have become unsafe, obsolete or economically unviable are being removed, says the report. Some 62,000 large dams and millions of small barriers have been built on rivers across the world, with an estimated 1.2 million in-stream barriers in European rivers. “By 2030, 89 per cent of global river volume will be moderately to severely impeded by fragmentation, a sharp rise from 43 per cent in 2010,” the UNEP report notes, citing a study. “While humans have benefited significantly from these services, nearly all barriers modify water flow and temperature, habitat quality and quantity, downstream sediment transport, and fish movement. Inland fisheries that communities depend on as local food sources can be devastated following the construction of a barrier, particularly large dams,” it adds.

In 2000, the EU recognised river-barriers as an anthropogenic pressure under its Water Framework Directive, after studies showed that one-fifth of the bloc's surface waterbodies were affected by barriers like dams and weirs. In July 2023, the European Parliament adopted the “Nature Restoration Law”, mandating that 25,000 km of rivers must be barrier-free by 2030. Welcoming the recent progress, Jelle de Jong, chief executive of WWF Netherlands, says, “Rise in removals showed that communities and governments were increasingly seeing the benefits of reconnecting and restoring rivers.”

With the removal of river-barriers picking up in the US as well, there is an opportunity to gauge how this intervention—which can last up to 50 years depending on a barrier’s life—impacts local ecosystems. Post-demolition, there will be chances to learn how the ecosystem returns to its natural self. Finally, “In much of Africa, Asia and South America, where barrier building far outpaces removal, hydropower dams are seen as a green option to provide energy that supports the needs of growing populations. This infrastructure can be carefully designed and placed on the landscape in ways and locations that minimize disturbances to river health,” suggests the UNEP report.

This column was originally published in the August 1-15, 2025 print edition of Down To Earth