Costs and water ecological state of the greatest inflow of Rosi river – river Rostavitsya

Purpose. To establish the flow and ecological state of the water of the Rostavytsia River, to assess the suitability of water for water supply and irrigation according to irrigation indicators. Methods. System analysis, methods of mathematical statistics. Results. An analysis of the long-term (1940-2019 with interruptions) results of the study of the morphological parameters of the riverbed, daily, monthly, average, maximum and minimum water flows per year, the dynamics of the chemical composition, mineralization of the water of the Rostavytsa River and the state of pollution by biogenic and specific substances of toxic action, heavy metals, petroleum products, phenols, SPAR in comparison for different periods of time: 1940-1947, 1972-1980, 2003-2010, 2011-2020, 2021-2022 is presented. It was determined that due to significant regulation of the flow, the spring flood is characterized by a slow increase in levels, the largest monthly water flows are characteristic of April, By the chemical composition of the water of the river Rostavitsa in 2000-2022 is characterized by average mineralization values, hydrocarbonate, calcium, medium hard, weakly alkaline. The highest salt concentrations were observed in 2007, 2016 and 2018. Water pollution of the Rostavitsa River with nitrite nitrogen is assessed as stable, moderately-highly polluted, with nitrite nitrogen - stable, moderately-highly polluted, with nitrates - the water is dirty. According to the water pollution index - the water is moderately polluted. Conclusions. The largest monthly water flows of the Rostavitsa River are characteristic of April, by chemical composition and mineralization the water is suitable for water supply, but the presence of toxic elements and substances such as iron, manganese, nickel, lead, cadmium, phenols, petroleum products in its composition requires water treatment and purification.