More than 1 million barriers destroying Europe’s rivers, new research shows

Posted on 29 June 2020

Europe’s rivers are congested with more than 1 million barriers, new research has found.
The scale of river fragmentation recorded by the study is alarming, making Europe the most obstructed river landscape in the world. These barriers - such as dams, weirs, ramps, fords and culverts - have a terrible impact on rivers, affecting river health, the quality and availability of water, and threatening the survival of vulnerable species.

The Pan-European Atlas of In-Stream Barriers, produced by the EU Horizon 2020 project Adaptive Management of Barriers in European Rivers (AMBER), is the most comprehensive overview of river fragmentation in Europe to date. It contains information on 630,000 barriers. However, after walking 2,700 km of streams in 28 countries, AMBER researchers have found that more than one third of barriers are unrecorded, bringing the total in Europe to well over 1 million. 

Carlos Garcia de Leaniz, AMBER project coordinator and Professor of Aquatic Biosciences at Swansea University remarks, “Even areas that were considered to be relatively pristine and well connected are in fact impacted by barriers. For example, in the Balkans, our field validation indicates that 80% of barriers do not appear in current inventories, making the fragmentation of these rivers much worse than people thought.” 

Traditionally, river managers have tended to view river fragmentation as being caused solely by large dams, but AMBER researchers have found this is seldom the case. In Europe, over 85% of barriers are weirs and other small structures. All barriers, whatever their size, impact on river health, changing a river’s natural flow, blocking fish migration routes -- affecting fish stocks and the survival of vulnerable species -- and trapping sediments that protect riverbanks and deltas against floods and sea level rises. Many of the barriers mapped by AMBER are out of use, and could be removed as they break river connectivity and block the movement of sediments and organisms

With hardly any free-flowing rivers left in Europe, the study adds to an already bleak picture. 60% of EU waters are currently not healthy [1], and freshwater species are amongst the most threatened in Europe - one in three European freshwater fish species threatened with extinction [2]. Urgent action is needed to reconnect Europe’s rivers. 

In the EU, there is hope: The European Commission just last week opted to safeguard the EU’s strong water legislation, the Water Framework Directive (WFD), with the EU’s Commissioner for Environment, Ocean and Fisheries, Virginijus Sinkevičius, underscoring the need to boost implementation and enforcement. Last month, the Commission also put forward a concrete commitment to restore at least 25,000 km of free-flowing rivers in the EU Biodiversity Strategy. 

The tools and commitments are there, but they are redundant unless fully implemented, enforced, and met with ambition and political will. EU Member States need to pull out all the stops to ensure the WFD works not just on paper but in practice, and to tackle the pressure of these barriers at the source. This should include drastically stepping up dam removals and barrier management in the next round of River Basin Management Plans (the plans Member States are required to submit under the WFD) for the period 2021-2027. 

Claire Baffert, Senior Water Policy Officer at WWF’s European Policy Office, said: “We need to bring free-flowing rivers back to Europe. The Water Framework Directive provides all the  right tools, as affirmed by Commissioner Sinkevičius just last week, but these need to be matched with far-reaching, ambitious action to remove barriers. Whilst the EU Biodiversity Strategy’s concrete commitments on river restoration are a promising start, they must be backed up with proper enforcement and dedicated funding.”

Barbara Belletti, who led the development of the AMBER Atlas at Politecnico di Milano along with Wouter van de Bund at the Joint Research Centre of the European Commission, commented, “Over 60% of EU freshwater systems are in a poor state in part due to habitat fragmentation. To improve the health of our rivers, we need to reconnect them—our Atlas and tools will support this endeavour.” 

The data collected through the AMBER project starkly complements the first Europe-wide mapping of hydropower plants, released by WWF last year, which found Europe’s rivers to be saturated with more than 20,000 hydropower dams, and more than 8,000 additional ones on the cards.


[1] European Environment Agency, 2018. European waters -- Assessment of status and pressures 2018,
[2] European Commission, 2011. European Red List of Freshwater Fishes,


For more information on the AMBER atlas:

Roxanne Diaz
AMBER Communications Manager
+31 618918786 

Victoria Hurst
AMBER Project Manager 
+44 (0)7967 870019 

Prof. Carlos Garcia de Leaniz
AMBER Project Coordinator and Principal Investigator
+44 (0)7891 615806 

For more information on EU water policy:

Sophie Bauer
Communications Officer (Water)
+32 471052511

Notes to the Editor: 

The Pan-European Atlas of In-Stream Barriers data can be used to estimate river fragmentation at various spatial scales. Together with several restoration tools specifically developed by the AMBER consortium, this information can help river basin managers minimize the impacts of barriers. For example, AMBER research indicates that most of the loss of connectivity is typically caused by a relatively small fraction of barriers, so it makes sense to prioritize these. The priority should be to protect the least fragmented rivers and to act on those barriers that cause most of the damage. 


The EU Horizon 2020 AMBER project seeks to apply adaptive management to the operation of dams and other barriers in Europe’s rivers to achieve a more sustainable use of water resources and a more efficient restoration of stream connectivity. The project has developed tools and simulations to help water companies and river managers maximize the benefits of barriers and minimize ecological impacts. AMBER promotes habitat connectivity and evaluates the merits of different restoration actions through an evidence-based and a what if simulation approach. 

All tools developed by the AMBER consortium will be available on the project website (www.amber.intenational) before the end of 2020. 
Caban Coch Dam, Wales
Caban Coch Dam, Wales
© Sara Barrento / AMBER
2,5m high barrier close to Belfast, Ireland.