Impacts of existing and planned hydropower dams on river fragmentation in the Balkan Region

The Balkan region has some of the best conserved rivers in Europe, but is also the location of ~3000 planned hydropower dams. A conflict between policies that promote renewable hydropower and those that prioritise river conservation has ensued. Using ground-truthed barrier data, we analysed the extent of current longitudinal river fragmentation in the Balkan region and simulated nine dam construction scenarios. Balkan rivers currently have an average barrier density of 0.33 barriers/km; this is 2.2 times lower than the mean barrier density found across Europe and serves to highlight the relatively unfragmented nature of these rivers. However, all simulated dam construction scenarios would result in a significant loss of connectivity compared to existing conditions. The largest loss of connectivity (−47 %), would occur if all planned dams were built, 20 % of which would impact on protected areas. The smallest loss of connectivity (−8 %) would result if only large dams (>10 MW) were built. In contrast, building only small dams (<10 MW) would cause a 45 % loss of connectivity while only contributing 32 % to future hydropower capacity. Hence, the construction of many small hydropower plants will cause a disproportionately large increase in fragmentation that will not be accompanied by a corresponding increase in hydropower. We encourage planners and policy makers to explicitly consider trade-offs between gains in hydropower and losses in river connectivity at the river basin scale.

CAROLLI Mauro;  GARCIA DE LEANIZ Carlos;  JONES Joshua;  BELLETTI Barbara;  HUDEK Helena;  PUSCH Martin;  PANDAKOV Pencho;  BORGER Luca;  VAN DE BUND Wouter; 

2023-02-08

ELSEVIER

JRC128605

0048-9697 (online),   

https://www.sciencedirect.com/science/article/pii/S0048969723005557,    https://publications.jrc.ec.europa.eu/repository/handle/JRC128605,   

10.1016/j.scitotenv.2023.161940 (online),