BiH: Scientists warn Buk Bijela dam project poses grave threat to Upper Drina Basin

Banja Luka, Sarajevo, Bosnia and Herzegovina – March 25, 2026 – In a scientific position paper, 163 experts have issued a stark warning about the proposed Buk Bijela Hydropower Plant (BBHP) on the Upper Drina River. The review finds that the 2025 Draft Environmental Impact Assessment (EIA) is fundamentally flawed, scientifically insufficient, and trivialises ecological damage, while ignoring cumulative and transboundary impacts on the Upper Drina (Bosnia and Herzegovina) and Tara (Montenegro) river system.

Although presented as a single dam, the BBHP is part of a cascade that actually envisions two additional hydropower plants downstream, as well as 11 smaller dam barriers in tributaries, including within Sutjeska National Park, to hold back sediments from the main reservoir. Along with other extensive river management structures, these measures would severely disrupt sediment dynamics, ecological connectivity, and fish migration, further threatening the survival of endangered species such as the Danube salmon (Hucho hucho). Put simply, hydropower expansion in the Upper Drina is incompatible with the survival of this globally significant river system.

“The proposed Buk Bijela Hydropower Plant, with its large size, hydropeaking operation, and extensive off-site engineering, represents the worst type of hydropower development for this region,” the undersigned scientists of the position paper stated. “It would cause severe and widespread ecological damage to the Upper Drina catchment and could drive one of the last wild populations of Hucho hucho to extinction”

The Upper Drina Basin, including its tributaries Tara, Sutjeska, Piva, Ćehotina, and others is of global conservation priority, hosting 42% of the remaining Balkan habitat for the Danube salmon or huchen—nearly one-third of its global distribution. The experts strongly reject claims in the EIA that reservoirs or hatcheries could improve genetic health. “This is nonsense and goes against all scientific evidence,” said Prof. Steven Weiss, University of Graz, Austria. “The truth is the opposite: building reservoirs destroys the natural, flowing habitats that Danube salmon need to survive. Turning these rivers into standing-water reservoirs is deadly for the species—a reality long established by decades of conservation genetic research. Large-scale hatcheries would be a nightmare scenario for conservation, risking serious harm to the salmon’s genetic health and threatening their long-term survival.”

Other major points of criticism of the EIA include its claim that Danube salmon in the Tara Canyon do not require spawning areas in the upper Drina, despite evidence and previous studies highlighting the need to identify these sites. The EIA also provides no plausible plan for a functional fish pass at a dam of this scale, misrepresents the species’ biology by falsely claiming that Danube salmon is not a true salmonid, and ignores the severe ecological impacts of constant hydropeaking. Overall, the assessment trivialises the river’s biological and hydrological needs, giving a false sense of security while threatening irreversible habitat loss and potential local extinction of endangered species.

Therefore, the scientific community calls for an immediate halt to all hydropower projects in the Upper Drina and its tributaries until a robust, comprehensive EIA is conducted. This assessment must include seasonal fish surveys, mapping of spawning and nursery habitats, modelling of hydrological and sediment changes, cumulative impact analysis of the Drina cascade, evaluation of genetic connectivity, and consideration of impacts on both upstream and downstream UNESCO sites, national parks, and transboundary waters.

“Our data show that in recent years all hydropower plants in Bosnia and Herzegovina have underperformed in production, yet these attacks on our rivers continue, and controversial projects like this are still being pushed”, stated Vladimir Topić from the organisation Centre for Environment (CZZS). 

According to recent media coverage in the Republika Srpska, the US company Bechtel has held discussions with authorities about potential cooperation and financing for the Buk Bijela Hydropower Plant. Foreign investment interests must not take precedence over rigorous scientific assessment or the long-term protection of the Upper Drina River and its ecologically important tributaries.

“This type of hydropower plant is totally 1960s style; it represents the worst of the dams that were built in the past, based on an EIA caricature. Approving this dam project would irreversibly destroy this river system of global importance and with it the core area of the largest salmonid on earth,” concludes Ulrich Eichelmann, CEO of Riverwatch. “We call on the Republika Srpska government to immediately halt this project and at least start a new EIA based on modern standards.