As a nongovernmental organization watching closely the hydropower development and practice in Bulgaria in the last 15 years, we, the members of Balkanka Association Sofia, have vast and negative experience concerning the devastating impact caused to the river ecosystems in our country. Here are some of the major reasons to explain the damage: - The reduced /or absent/ river flow and the water quality degradation - The blocked sediment downriver transportation - The river fragmentation disrupting bio corridors for fish and other aquatic species migration. Most of these things happened to the Danube River many years ago, when the Iron Gates HP Unit was built. Before that the River was so rich of life that sometimes professional fishermen had troubles taking out the heavy nets full of fish while the author was watching them as a child. Many of the River species are threatened in the Bulgarian section of the River nowadays.