New WWF Analysis Reveals the Possibility of Freeing at Least 7800 km of Rivers in the Region from Unnecessary and Environmentally Harmful Barriers

The study demonstrates the massive potential of barrier removal to restore free-flowing rivers and nature in the Green Heart of Europe.

19 April 2021 – WWF’s new Potential of Barrier Removal to Reconnect Europe’s Rivers report analyses a sample of 30,000 barriers on large and medium-sized rivers in Europe, and assesses their reconnection potential for the whole continent, the EU27, and by country. The conclusions are based on the length of river which could be reconnected, and the ecological quality of reconnected rivers which could be achieved through barrier removal.


The scale of river fragmentation makes Europe the most obstructed river landscape in the world. In Europe, over 85% of barriers are small structures such as weirs, ramps, fords and culverts. All barriers, whatever their size, impact on river health; changing a river’s natural flow, blocking routes for critically endangered migratory fish species such as sturgeon, and trapping sediments that protect riverbanks and deltas against floods and sea level rises.

One of the primary drivers of the decline of freshwater biodiversity in the Danube basin are dams and other water infrastructure that impact the natural habitats of freshwater species like Danube sturgeons, Danube salmon and other fish, otters, and thousands of other species in the region.” - Irene Lucius, WWF-CEE


Out of the sample studied in the report, less than 3% of Europe’s estimated 1 million barriers [3], 732 barriers were identified as having a high reconnection potential, and which would enable the reconnection of about 11500 km of large and medium-sized rivers in the EU. A further 6,628 were identified as having a good reconnection potential.  A total of nearly 50,000 km of rivers show a high and good potential to be restored to free-flowing again. The research concluded that there are 781 barriers with removal potential in Bulgaria, Hungary, Romania, Slovakia and Ukraine - representing 7828 km of potential river reconnection.


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Restoring natural flows in Central and Eastern Europe

WWF-Slovakia successfully crowdfunded for removal of weir barrier on the Hucava River in Central Slovakia.

The weir is an obsolete barrier blocking the natural flow and function of the river. The Hucava is host to an abundance of species including the Noble crayfish, Eurasian otter, common kingfisher, the Black stork and many important fish species. Removal of the weir is planned for the second half of June. 

Within Verhovynskyi National Park, Ukraine, there are five splash dams that must be removed or modified to restore river connectivity for fish migration and spawning. No Carpathian river splash dam has been used since 1979. They have gradually decayed over time, though they still serve as obstacles for migratory fish such as brook trout and endangered Danube Salmon. Following a successful international crowdfunding campaign, the Lostunets Dam was the first dam to be removed last year under WWF-Ukraine’s new Splash Dam Removal Project.


Dam removal is the fastest, easiest and cheapest measure to restore a river

Its efficiency has been proven on dams all over the world. The time between removal and total recovery of the river is very short. Within a few months a river can regain its territory, water quality improves dramatically, aquatic and terrestrial wildlife numbers boom, and the overall services that a river in good ecological state provides to humans regain their function.

The upcoming revision of River Basin Management Plans in Bulgaria, Hungary, Slovakia and Romania offers a unique opportunity to include measures and budget to restore rivers, floodplains and wetlands to ensure the proper implementation of the EU Water Framework Directive, as well as contribute to reaching the free-flowing river objectives stated in the 2030 EU Biodiversity Strategy. Recovery funds, meanwhile, can still offer a last minute chance to finance these kinds of operations.


Dam removal and EU nature restoration targets

The European Commission will release its proposal for legally binding EU nature restoration targets by the end of 2021. The target on free-flowing river restoration through barrier removal is crucially needed to halt the decline in freshwater biodiversity and complement the requirements set by the Water Framework Directive.  This new analysis makes clear that the European Commission’s new Nature Restoration Law should and could aim much higher than its current target to maximize restoration potential for freshwater ecosystems.


The removal of obstacles from rivers is a key tool to recover the functionality of rivers,” said Eva Hernández, WWF’s Living European Rivers Initiative Lead, and adds “If we want to reach the Green Deal objectives, if we want a resilient landscape that allows nature and people to adapt to climate change, we need to look at our rivers and start freeing them from all the obstacles that have piled in them over the last century.”


Further information:

Irene Lucius

Regional Conservation Director,

WWF Central and Eastern Europe

Tel: +43 1 52 45 470 19,


Read full report here




With 1000 hydropower plants, 400 more are planned or under construction, Bulgaria, Hungary, Slovakia, Romania and Ukraine are already saturated. The Danube catchment is becoming one of the most affected large river catchments not only in Europe but also worldwide. The Danube’s flow is being impeded by the Iron Gates Dams at river kilometre 863, hindering highly threatened migratory sturgeons and other fish from entering important spawning and feeding sites in the Middle Danube. The Olt River, originating in the Carpathian Mountains, is covered by a long chain of hydropower plants. Numerous new projects are appearing. They include two large dams on the Lower Danube, which date as far back as the Soviet rule, and many new small hydropower projects in Ukraine. 2,500 (28%) of all planned hydropower is in protected areas (33% in the EU); such as two hydropower projects threatening Natura 2000 sites in Romania: one in Defileul Jiului National Park and the other in Răstolița where the government recently modified legislation to open up dam construction in all protected areas across the country.


However, the environmental opposition against new dams is high. WWF-CEE is addressing threats to rivers and wetlands, including dangers posed by inappropriate dams and other infrastructure; promoting guidelines and best practices for the development of hydropower to provide security of planning for investors; and ensuring that clean and renewable energy from water does not come at too great a price in terms of other ecosystem goods and services. Some of the projects on larger rivers might be suspended such as those on the lower Drava, where the recently designated 5-country Mura-Drava-Danube Biosphere Reserve managed to change the narrative. Advocacy by WWF-Romania and its partners prevented EU funds from financing harmful flood infrastructure projects at Colibita and Gurasada. In a case initiated by WWF, Romania’s highest court ordered a stop to construction of a dam on the Jiu River. In Ukraine, construction of a planned cascade of six hydro plants on the Dniester River has been frozen. The Drava River Campaign with WWF-Adria placed 2 hydropower plants along the Drava on indefinite hold. WWF-Slovakia and other Slovakian NGOs were instrumental in challenging a dam siting decision which led to the Supreme Court of the Slovak Republic definitively stopped the licensing of a small hydroelectric power plant in Žiar nad Hronom. In the landmark decision, the Slovakian Supreme Court said, “The public interest, which is the protection of the environment, takes precedence over private business interest.”




Hucava River, Slovakia

Hucava River, Slovakia

© Miroslav Ocadlik

Removal of the Lostunets Dam, Ukraine

Removal of the Lostunets Dam, Ukraine

© © WWF-Ukraine