With the water framework directive (2000/60/EG) and the renewables directive (2009/28/EG) the European Union created extensive works, theirs implementation should simultaneously result in a successful protection of our water bodies and to an increase of energy production out of renewable energy sources. In terms of hydropower these targets implement a wide range of conflicts. The present work represents measures accounting both goals. The optimization and enhancement potential of existing hydropower sites, the multifunctional utilization of drinking water and artificial snow systems and the development of an ecological and economical modified Fishpass is discussed. Within the scope of a hydropower potential study for the federal state Salzburg a revitalization potential for 404 sites < 5 MW of 455 GWh/a was discovered. For sites larger than 5 MW this potential amounts 300 GWh/a. At 180 possible sites for drinking water hydropower plants, a power production potential of 16 GWh/a was derived. Pump storage hydropower plants at existing artificial snow lakes can produce 1.430 GWh/a of valuable regulation and compensation energy. The potential obtained by optimizing necessary ecologic measures is exemplified with a hydraulic further development of a Fishway. The newly designed concept, named Multi Structure Slot Fishpass, was tweaked to reach a maximum ecologic acceptance by reducing the necessary discharge which is also considered positive among hydropower plant operators. The investigations were carried out at a physical 1:5 and 1:1 hydraulic model. With additional roughness elements, a longitudinal extension of the slot and an additional guidance wall, the slot area was remodelled in order to gain a multi structured slot. These measures evoke additional hydraulic losses and an intended meandering flow in the resting pool which result in a major discharge reduction between 33 % and 45 % compared to the discharge of a common Vertical Slot fishway with identical design parameters. Flow velocities at sensitive fish migration sections were reduced considerably of about 25 %. Fish trials at the 1:1 hydraulic model approve the biologic acceptance of the new, low turbulent fishway system.