The publication “BREAK FREE – Restoring the biodiversity of rivers by removing dams” addresses the effects of barriers on migratory fish highlighting the worrying and catastrophic situation on the Mekong River (going across 5 countries in Asia) where the constructions of hydropower dams are putting not only the river and its components at risk but also all the already vulnerable populations depending on the Mekong River. The intensive use of water for agricultural irrigation can even lead to the complete drying out of the river bed as it is the case for the Colorado River. A Number of dam construction projects are also on the table in the EU, including Northern Italy. On the other hand, there are striking examples of dam removals in the USA that show the efficiency of dam removals on biotopes and ecosystems restoration. In Europe such examples can also be found in France where 2 big dams are currently being removed at the Sélune River and in Finland where dam removal meanwhile is a more common practice.
According to the EU Biodiversity Strategy 2030 at least 25,000 km of rivers need to be restored into free-flowing rivers through the removal of primarily obsolete barriers and the restoration of floodplains and wetlands. The EU Commission released a guidance reporting one dam or weir every 1.5 km on European Rivers. Dams have different purposes, like hydropower or water supply, but many structures are ageing and some don’t fulfil their originally intended purpose, anymore. Whereas it is mandatory to consider the removal of ageing dams, severely impairing migratory fishes, the question of hydropower, especially in energy crises such as we live nowadays, must also be properly addressed.