Ecological assessment of the Zaporizhzya (Dniprovsky) reservoir

Abstract

Environmental assessment of water is an integral part of monitoring water bodies. It provides information about water as a component of the aquatic ecosystem, the habitat of hydrobionts and an essential part of the natural environment, which is necessary for establishing environmental standards for water quality and adoption of measures to improve the ecological state of water bodies. Assessment of the quality of the ecological environment is an important parameter of sustainable development, necessary for the rational use of nature. Currently, the Zaporizhzhia (Dnipro) reservoir is exposed to increased anthropogenic impact, which affects water quality. The ecological state of the reservoir is deteriorating, and mass algal bloom is observed. The work aims to provide an integrated environmental assessment of water quality in different sites of the Zaporizhzhia reservoir. The study was conducted in 2019 at 5 sites along the course of the Zaporizke reservoir, which differ in hydrological and hydrochemical conditions: Samara Bay, Festivalnyi pier, Monastyrsky island, creek of the Mokra Sura river and the lower section of the reservoir (near Viyskove village), following generally accepted hydrobiological methods. The article calculates block indices and provides an environmental assessment of the water quality of the Zaporizhzhia reservoir according to the "Methodology for environmental assessment of surface water quality in the corresponding categories. The assessment of water quality by the criteria of contamination with salt composition components indicates that the water body condition is good at most of the studied points. The worst indicators were recorded in Samara Bay, where increased mineralization is observed for a long time. The trophic-saprobological block revealed to have the worst indicators and a high amplitude of index fluctuations. No significant deviations were observed in terms of the content of toxic and radiation exposure indicators throughout the entire studied water area, which makes it possible to assign water to the same class. It has been determined that the water quality of the Zaporizhzhia reservoir according to the average annual data is characterized as "good" in terms of the state and "clean, fairly clean" in terms of purity degree. However, during the study period, significant deviations from the average were observed, especially in the summer. There is a need for systematic monitoring of the reservoir, the establishment of annual dynamics, which will make it possible to determine the causes of deteriorating water quality and develop ways to address them.