The importance of sustainability in today’s water management is unquestionable. Therefore, it is also recommended to apply the principle of sustainability in river management, such as it is the aim of the ongoing Ancient Dráva project. The term, environmental flow, intends to comprise a complex methodology not only from biophysical but also from a social angle; considering the different aspects of each method. Our target is to determine a possible holistic method which could be applied to the Dráva and its hungarian floodplain in oder to find a possible solution to the reconnection of the oxbow lakes into river mechanism. Our research is mainly based on hydrological data (Qmin, Qmax, Hmin, Hmax), but we will consider the special needs of the ecological environment, too.