In order to asses and evaluate the ecological potential of dammed storage reservoirs we need insight into the spatial structure of their hydrodynamics. This structure is influenced by a number of internal and external factors that may depend on each other. To understand these factors better it is necessary to find dependencies between them, to develop methods and techniques of building scenarios that integrate spatial and temporal features of the subsequent hydrodynamic “states” of the reservoir. These scenarios are meant to be the physical base for any subsequent biochemical water quality assessment within the given reservoir. This article presents the basics of the proposed techniques along with their applications on two multi-purpose storage reservoirs located in southern Poland within the upper Vistula River catchment: Dobczyce and Goczałkowice. Preparing the observational data for their use in numerical models and the application of these models and a few preliminary results obtained for real-life issues regarding the chosen reservoirs are presented and discussed. The possibilities of generalizing the proposed techniques toward a methodology of hydrodynamic conditions assessment for improving the ecologic potential of dammed reservoirs is also briefly outlined.