For a long time, thermal power plants (TPPs) have been a source of significant anthropogenic pressure on the environment. None of the natural components remains unchanged. The load on aquatic ecosystems, the creation of special conditions for hydrochemical processes, the formation of new connections and interdependencies between they require a detailed analysis of chemical, physical and biological data, modelling of various strategies and planning to understand the changes that have occurred and to analyse their dynamic scenario in the next years. The aim of the study is to analyse the long-term impact of typical Burshtyn TPP pollution on the water bodies around it and to track their spatial and temporal behaviour using statistical analysis in order to improve the environmental safety of the Dniester tributaries flowing through Rohatyn Opillya and to identify the opportunities for more efficient management of the hydrological system. The study analysed the content of pollutants in water samples collected during 1993-2024 from ten locations in the Burshtyn Cooling Reservoir (BCR), the Dniester River and the Hnyla Lypa River (HLR), which form a connected water system influenced by continuous work of the Burshtyn TPP. The statistical analysis confirmed a series of slow changes in the contents of Ca and Mg. Therefore, slow but monotonous dynamics in the changes of water quality in the connected hydrological system HLR & BCR & Dniester River during the last 30 years of a hydrochemical load by the Burshtyn TPP, has been confirmed by a detailed statistical analysis оf data selected independently in recent years and of the data available from the open sources. The results confirm that the water system considered can be used as a model system for mathematical estimation of the technological harm, ecological safety and the self-restoration abilities of such systems.