Regularities of anthropogenic pollution of water resources

Hydrotechnical structures are critical infrastructure for global water resources management, yet their operation is accompanied by significant environmental consequences that become particularly relevant in the context of climate change and intensification of anthropogenic pressure. The aim of this work is a comprehensive analysis of patterns of anthropogenic pollution of water resources by hydrotechnical structures based on the synthesis of scientific publications from 2023-2025. The study covers mechanisms of pollutant accumulation in reservoirs, scales of sedimentation and loss of storage capacity, patterns of heavy metal pollution, the impact of thermal stratification on water quality, and modern strategies for minimizing negative impacts. The methodological basis of the work is a systematic review and critical analysis of contemporary scientific research. Particular attention is paid to regional differences in the scale of impact and correlational dependencies between reservoir characteristics and pollution levels. Key patterns of anthropogenic pollution have been identified: progressive sedimentation with regional variability, which will lead to a loss of 25-26% of global reservoir storage capacity by 2050; a two-sided sedimentation effect with sediment accumulation in the upper reaches and ecosystem degradation downstream; a three-phase model of heavy metal pollution with sequential stages of low pollution, rapid pollution, and pollution control; a paradoxical distribution of pollutants with decreasing concentrations in the water column while increasing content in bottom sediments; age-dependent and urbanization-dependent accumulation of heavy metals; a thermal-geochemical relationship that intensifies eutrophication through internal phosphorus remobilization and creation of hypoxic conditions. It has been established that cadmium concentrations can exceed background values by 6-7 times, and older reservoirs demonstrate a loss of storage capacity up to 50%. The scientific novelty of the work lies in the systematization and generalization of the most recent research from 2023-2025, which integrates knowledge about sedimentation, heavy metal pollution, thermal stratification, and ecological consequences into a unified interdisciplinary framework for understanding the anthropogenic impact of hydrotechnical structures. The practical significance of the study lies in substantiating the need to implement comprehensive reservoir management strategies that include environmental water releases, artificial destratification technologies, and sediment management programs to minimize long-term environmental risks. The results of the work can be used in developing national water resources management strategies, planning environmental monitoring of reservoirs, and assessing the environmental impacts of new hydrotechnical structure construction. Further research should be directed toward developing predictive models of pollutant accumulation considering climate change and creating adaptive water quality management systems in reservoirs under conditions of increasing anthropogenic pressure