In the Water Framework Directive in 2000 the European Parliament concluded a joint legislation for the conservation and improvement of ecological water quality of surface water in the countries of EU. So in the hydropower development has also to be considered to maintain the good ecological water status to all expansion wells. The preservation respectively the restoration of the ecological connection of the water systems are of particular importance, especially the up-river and down-river fish migration. A further focus lies on the preservation/restoration of the typical river ecological structure in order to maintain the natural habitats of the variety of water biocoenosis. For the implementation of this targets the water ecologist and the hydraulic engineers are required to search and to find with innovations and technically possible the best solutions for reaching the joint goal. The discussed examples from Austria and Germany demonstrate that the ecological and hydro technical requirements of the EU Water Framework Directive for the modern hydropower construction are technically possible and realizable.