Small hydro | Quantifying impacts
New research into the impact of small hydropower development across the Balkans aims to help decisionmakers better understand the consequences of such plans by quantifying trade-offs between gains in hydropower capacity and losses in river continuity
AS INTEREST GROWS IN untapped hydropower potential across the Balkan region, authors of a new paper published in Science of the Total Environment express concern about the area which is considered to have some of the best conserved rivers in Europe. With plans to develop numerous hydropower dams, Carolli et al say conflict between policies which promote renewable hydropower and those which prioritise river conservation has ensued, and this can only be resolved with the help of reliable information. Described as a global hotspot for freshwater biodiversity, the authors claim that the Balkans is also one of the world’s regions with the greatest proportion of native freshwater fauna threatened by hydropower development. Predictions suggest that more than 60% of native endangered freshwater fish could become extinct or near extinct if all planned hydropower projects were built. Information on the continuity of Balkan rivers is scant and barrier data hard to obtain, and this can make the assessment of current levels of fragmentation and the evaluation of the impacts of planned hydropower particularly difficult to assess. In their study, Carollie et al assessed the extent of river fragmentation in the Balkan region by building on a recent pan-European inventory of longitudinal barriers. This enabled them to calculate several indices of river connectivity and identify the best connected (ie least fragmented) basins. Secondly, they used what if
Above: Location of unique barrier records listed in the AMBER Barrier Atlas (all barrier types; Belletti et al., 2020) and planned hydropower dams in the Balkan region. Barrier data is underreported by 38–98 % across these countries (mean = 85 %) Source: Carolli et al
Right: Predicted changes in river fragmentation measured as Barrier Free Length (BFL, km) between (a) existing conditions; (b) worst case scenario (scenario S1, all planned hydropower dams are built); (c) only small dams (10 MW) are built (scenario S4) and (d) only large dams (>10 MW) are built (scenario S3) Source Carolli et al.
34 | September 2023 |
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