Europe’s rivers look very different from when much of the infrastructure shaping them was built. We are asking whether the decisions governing that infrastructure have kept pace.
This summer, low water levels on the Danube and Rhine disrupted freight, industry, and energy production across Europe. Rivers suddenly became difficult to ignore – as landscapes and habitats, but also as systems that our economies and communities depend on.
Many of the structures shaping those rivers have been there for decades. Large dams built in the 1960s and 1970s are still operating. Smaller barriers remain scattered along waterways, including structures whose original purpose has disappeared altogether.
And while rivers change, the decisions governing that infrastructure do not always change with them.
A dam built in the mid-1970s is now around 50 years old. The climate that such a structure was built for no longer exists.
Today, Europe faces changing rainfall patterns, more severe drought conditions and changing river flows. Scientific knowledge has advanced, environmental standards have changed, and the purpose a structure was built to serve may look very different. Over the same period, sediment can build up behind a dam, reducing reservoir capacity.
Yet in some cases, a dam can continue operating for another 20 or 30 years without an environmental impact assessment reflecting those conditions.
That is the problem examined in ClientEarth’s report Past the Expiration Date, which looks at dam lifetime extensions and EU environmental law through case studies in Poland, Italy, Bulgaria, and Romania.
Ageing does not automatically mean obsolete, but still standing doesn't mean still serving its original purpose.Maja Starosta, Law and Policy Advisor at ClientEarth, author of "Past the Expiration Date".,
Not every barrier is a huge concrete dam. Europe’s rivers are fragmented by an estimated 1.2 million artificial barriers. Many are small. More than 100,000 are estimated to be abandoned or obsolete.
They may no longer be useful, but they are still there – interrupting the movement of water and sediment and preventing migratory fish from reaching feeding and spawning grounds. Removing one might sound straightforward, but in practice, it can raise a surprising set of questions.
Does anyone know the barrier exists? Who owns it? Who is allowed to remove it? Who pays? If there are no good answers, then the barrier stays.
That is where ClientEarth’s second report, Freeing Europe’s Rivers, begins. Looking at Poland, Finland and France, it explores the less visible side of river restoration: the inventories, laws, responsibilities, procedures, and funding that determine whether removal actually happens.
We depend on rivers for water, food, and energy. They help us cope with too much or too little water. Healthy rivers are part of our safety net.Maria Włoskowicz, Legal Expert at ClientEarth, author of "Freeing Europe’s Rivers".,
Under the EU Nature Restoration Regulation, Member States must contribute to restoring at least 25,000 kilometres of rivers to a free-flowing state by 2030. Their draft national restoration plans were due on 1 September 2026.
However, a target alone won't remove a barrier. Countries need to know what is in their rivers: which structures still serve a justified purpose, which need to be reassessed or modified, and which have become obsolete. They also need legal and administrative systems capable of turning those decisions into action.
The same principle applies to ageing dams. Europe’s rivers are not the rivers of the 1970s. The climate, the science, the needs – they're all different.
The decisions shaping our rivers need to catch up.
ClientEarth experts answer frequently asked questions.
No. Some dams and barriers continue to serve important functions. What we are calling for is a case-by-case assessment of whether existing dams should continue operating for decades to come. Before major upgrades or permit renewals, large dams should be subject to environmental impact assessments (or screenings in the case of smaller dams and reservoirs), just as new infrastructure projects are.
An environmental impact assessment does not, in itself, predetermine dam removal. When carried out properly, it helps assess the environmental, climate, public health and safety implications of a dam's continued operation, including whether it poses risks to people or the environment due to the possibility of failure. This allows for a realistic cost-benefit assessment of future dam management options.
In some cases, a dam's continued operation is justified. In others, alternatives such as modification, improved fish passage or, where appropriate, partial or full removal may deliver better outcomes for people, nature and public finances in the long term.
Some dams do play an important role in flood control, and we do not contest that.
However, first, not all dams were built for that purpose. In the EU, only 6% of single-purpose reservoirs were built for flood control, and only 19% of multi-purpose reservoirs have flood control as their primary function; water supply, irrigation and hydropower are generally more common uses of dams in the EU[1].
Second, dams are only one of many tools available. Modern flood management also includes restoring wetlands and floodplains, improving land-use planning, strengthening early warning systems, and protecting natural water retention areas. In many cases, combining these approaches can provide more resilient and cost-effective flood protection than relying solely on reservoirs. The most appropriate solution depends on local conditions and should be assessed on a case-by-case basis.
Third, it is important to recognise that the effectiveness of dams can decrease over time. Reservoirs gradually lose storage capacity due to sedimentation, while ageing infrastructure may itself become a source of risk if not properly maintained.
Hydropower is considered a renewable source of energy, but renewable does not mean impact-free. Dams are known to have significant effects on river ecosystems, water quality, biodiversity and sediment transport.
We believe authorities should periodically assess whether individual facilities continue to deliver sufficient benefits in light of their environmental, social and economic costs.
Moreover, the conditions under which many dams operate today have changed significantly. Climate change, increasing water scarcity, longer and more severe droughts, and increasingly low river flows mean that some dams no longer perform as originally intended. This also affects hydropower generation. For example, this year’s drought has led to significant losses in hydropower production across the EU. The massive hydropower plants bordering Romania and Serbia, Iron Gate I and Iron Gate II on the Danube River, have been generating only 20% and 30% of their average electricity output, respectively[2]
The question is not whether hydropower is renewable, but whether a particular dam continues to deliver benefits that justify its environmental and economic costs. In some cases, the answer is yes. In others, alternative solutions, modifications or, where appropriate, partial removal may provide better outcomes. Each case should be assessed individually rather than decided in advance.
It is important to distinguish between drought and water supply.
A reservoir can provide a reliable water supply to particular users or regions by storing water, but it does not create new water. Removing a dam or reservoir may therefore require changes to how water supply is managed, particularly where communities or agriculture depend on stored water.
Drought, however, stems from a lack of available water across the wider catchment. Reservoirs can help redistribute water over time, but they are not always the most effective solution to drought risk.
Barrier removal does not necessarily worsen drought. In many cases, restoring rivers and floodplains can improve the landscape's natural ability to retain water, recharge groundwater and support more resilient water systems. Whether a barrier should be removed therefore depends on a case-by-case assessment of its benefits, costs, available alternatives and the needs of local communities.
In other words, the question is not whether water should be stored, but how it can be stored in the most effective, sustainable and climate-resilient way. We advocate for decisions based on evidence and cost-benefit analysis, taking into account environmental impacts, climate change and the long-term functionality of water infrastructure.
No. An environmental impact assessment does not, in itself, predetermine dam removal. When carried out properly, it can help assess the environmental, climate, public health and safety implications of a dam's continued operation, including whether it poses risks to people or the environment due to the possibility of failure. It also ensures public participation in decisions about the future of dam management.
The EIA process requires authorities to consider reasonable alternatives and justify the option ultimately selected. This helps prevent dam operating permits from being automatically extended or renewed and instead encourages a realistic assessment of future management options. Such an assessment should take into account environmental impacts, the effects of climate change, the heightened risk of failure associated with ageing infrastructure, and the long-term functionality of water infrastructure.
In some cases, an assessment may support the continued operation of a dam. In others, it may identify better alternatives, such as modifications, improved fish passage or, where appropriate, partial or full removal.
Under Article 9(1) of the Nature Restoration Regulation, Member States and their competent authorities must create a comprehensive inventory of artificial barriers to surface water connectivity. This includes all barriers created by human activities. The inventory is primarily a mapping exercise and does not mean that the listed barriers will automatically be removed.
The inventory is needed because barriers are significantly underreported across Europe. A landmark 2020 study[3] conducted in 36 European countries found that existing databases substantially underestimate the number of barriers. During surveys covering 2,715 km of rivers, researchers identified 1,583 barriers, 61% of which were missing from official inventories. On average, the number of barriers recorded in the field was 2.5 times higher than the number included in existing databases.
Once the inventory has been completed, Member States must assess the barriers, taking into account their social and economic functions, and identify those whose removal would contribute to achieving river restoration targets under the Nature Restoration Regulation. When prioritising removals, Member States are required to focus first on obsolete barriers.
The Regulation defines obsolete barriers as those that are no longer needed for renewable energy generation, inland navigation, water supply, flood protection or other legitimate purposes. This may include barriers whose original function has ceased, whose permit or licence has expired without renewal, or which have fallen into disrepair or abandonment. Examples may include old watermills, irrigation weirs or industrial diversion structures that no longer serve a useful purpose[4].
Member States should not repurpose obsolete barriers solely to avoid their removal or artificially extend their lifespan.
The Nature Restoration Regulation sets a target of restoring at least 25,000 km of rivers to a free-flowing state by 2030. A free-flowing river is one whose natural connectivity and ecological functions are not significantly hindered by artificial barriers.
The 25,000 km target is an EU-wide objective, to which all Member States must contribute. To achieve it, countries must identify and map artificial barriers, prioritise obsolete ones for removal, assign responsibilities and funding, and establish workable procedures for barrier removal.
Restoring 25,000 km of rivers is an ambitious goal, but evidence suggests it is achievable. A WWF analysis[5] of 30,000 barriers, representing less than 3% of all barriers in Europe, found that barriers with high reconnection potential alone could restore approximately 11,500 km of rivers. When barriers with good reconnection potential were included, the total exceeded 50,000 km of rivers with strong restoration potential.
The European Commission will support Member States by providing technical guidance and helping to mobilise funding. However, some countries will also need legal and administrative changes to make barrier removal easier and more effective in practice.
France provides one of the strongest examples of a systematic approach to river restoration and barrier removal in Europe. It has established a national barrier inventory, legal categories for rivers requiring protection or restoration, prioritisation criteria, and dedicated public funding. Approximately 1,400 structures were removed between 2012 and 2023. France also had a significant head start, having begun implementing river connectivity measures soon after the Water Framework Directive entered into force. As a result, some Member States are now effectively 30 years behind.
Finland has also achieved significant progress through publicly supported voluntary programmes such as NOUSU. Its approach relies more heavily on cooperation with barrier owners and other stakeholders, rather than on a comprehensive regulatory framework.
Neither system is perfect, but both demonstrate that barrier removal can be carried out in a structured and practical way. Their experiences offer valuable lessons for other countries seeking to restore river connectivity and implement the Nature Restoration Regulation.
