Upper Horizons hydropower scheme, Bosnia and Herzegovina

The 160 MW Dabar hydropower plant is part of the massive Upper Horizons (Gornji Horizonti) scheme, first conceived in the middle of the 20th century. Upper Horizons consists of three hydropower plants (Dabar, Bileća and Nevesinje planned), two reservoirs with multiple dams (planned), 4 diversion tunnels (2 built, 1 under construction, 1 planned), 1 pumping station (planned to divert water from Gatačko polje), 4 karst fields drained by large channels (Fatničko built, Dabarsko and Nevesinjsko to start construction in 2023, Gatačko planned). The longest tunnel, Nevesinjsko field – Dabar hydropower plant, is being built by the company Integral Inženjering PLC, owned by the controversial businessman Slobodan Stanković, a close associate of the Republika Srpska president Milorad Dodik and placed on the US sanctions list.  

The potential impacts from the project are hotly debated and may be extremely far-reaching. It is likely they are not all understood due to the complexity of the karst underground. First, the unique karst fields (poljes) in Republika Srpska would be completely destroyed. Underground karst rivers, caves and springs will be left with almost no water even before their biodiversity is properly studied. Three endemic fish species (Telestes dabar, Telestes metohiensis, Delminichthys ghetaldii) would probably be driven to extinction.

Second, the project would also involve closing or drying several sinkholes, which may endanger the water flow to the iconic Buna, Bunica and Bregava rivers that are of crucial importance to towns in the Federation of Bosnia and Herzegovina like Blagaj and Stolac as well as being home to protected species.More than 85 per cent of the water of these rivers would be diverted towards the Bileća artificial reservoir, and most of it will not be returned to the Neretva basin. The Biograd sinkhole in the Nevesinjsko karst field, one of the biggest in Europe, will be among the impacted.  The already seriously impacted Hutovo blato wetland, which is of international importance according to the Ramsar convention, would receive even less water if all parts of Upper Horizons are built.

Third, the project would decrease the flow of the river Neretva, whose delta in Croatia is already suffering from salination. As an important wetland and agricultural area, this in itself is a massive impact.

An environmental impact assessment (EIA) was carried out for the Dabar hydropower plant in 2012, but the Upper Horizons scheme as a whole has never been subject to either a strategic environmental assessment or an EIA, nor will the Dabar EIA have taken into account the increasingly erratic rainfall and hydropower production that have characterised the last few years.

The project has faced strong public opposition in both the Federation of Bosnia and Herzegovina (FBiH) and Croatia, and the FBiH government launched a court case against the EIA approval in 2012. Since the relevant court was in Banja Luka, it unsurprisingly ruled in favour of the Republika Srpska authorities. 

Although some tunnels have already been built, for some time the project did not seem to be moving forward, and the strong public outcry from earlier years seemed to abate. However, the announcement in January 2022 that a financing contract had been signed with the China Exim Bank saw renewed controversy. Given the likely seriousness of the impacts of the Upper Horizons complex, public opposition to the project – and corresponding political opposition – in FBiH and Croatia is expected to increase rather than decrease in the future.