Abstract
The continued high level of anthropogenic impact on natural water bodies inevitably leads to a deterioration in their ecological state. In such conditions, farmers need to ensure control over the quality of water resources, which can be achieved through physical and chemical monitoring. Despite the advantages of this approach, the existing limitations in interpreting the results, especially in eutrophic water bodies, pose a significant obstacle to its widespread implementation in practice. The article presents an attempt to develop a methodology for accounting for the eutrophication factor when monitoring water bodies using the physical and chemical method, which provides a better interpretation of the obtained data and makes it possible to implement this type of monitoring process in eutrophied waters. This methodology is based on the variability of basic hydrochemical parameters of the aquatic environment (pH, dissolved oxygen concentration, total mineralization), which are subject to variability as a result of phytoplankton activity. In 2022–2024, in the Central Reach of the Kuybyshev Reservoir, correlation relationships between the density of phytoplankton clusters and the content of dissolved oxygen (0.56…0.77), hydrogen index (0.49…0.63), and total mineralization (-0.57…-0.72) were determined to confirm the hypothesis about the possibility of using these indicators together in the monitoring process of eutrophic waters. The research results revealed a stable moderate-high correlation between the studied variables, as well as a specific pattern of their variability depending on the presence of phytoplankton in the water. Based on this interaction, the above-mentioned methodology has been developed, which involves the determination of three new values: specific variability of hydrochemical parameters (KD), the degree of influence of the phytoplankton factor on hydrochemical parameters (FD), as well as the amount of phytoplankton present in the aquatic environment (P). These indicators make it possible to expand the capabilities of standard physical and chemical monitoring in the context of widespread anthropogenic eutrophication and assess the suitability of water bodies for agricultural practices.