The study demonstrated that SWAT evapotranspiration estimations were in good agreement with those of the Budyko curves, whereas SWAT baseflow underestimated the Inn and Austrian Danube regions. The analysis of the Budyko equations in each water management region of the Danube provided a pioneering understanding of the relationship between EI and BFI in the study area, leading to an improvement of the hydrological simulations and providing a more reliable water balance in each water management region.