The main intent of this thesis is the evaluation, through modelling scenarios, of how large-scale water flows patterns in Germany would be modified if reservoirs were missing. This issue is not too popular among the scientific panorama, that, being quite divided on the question of dams bringing more advantages to people and economy or disadvantages to the environment and the ecosystems, often focus their studies on a single catchment or small geographical areas. To evaluate the relationship between rivers discharge and the action of the dams, machine learning tools are exploited to run SALTO. SALTO is a distributed conceptual rainfall‐runoff model on large scale that was first locally and then regionally calibrated with the PASS approach, an algorithm that works without any previous definition of the dominant catchment descriptors controlling regional patterns (Merz, Tarasova and Basso, 2020).