WATER STATUS OF ONE RIVER AND SELECTION OF RESTORATION MEASURES

Abstract

The article analyses the physicochemical indicators of the Praviena River, located in the municipality of Kaišiadorys district, which belongs to the Nemunas small tributary basin, and evaluates the ecological class of water quality and analyses the potential measures for its restoration. The indicators analysed are: nitrate nitrogen (NO3-N), ammonium nitrogen (NH4-N), total nitrogen (Nb), phosphate phosphorus (PO4-P), total phosphorus (Pb), biochemical oxygen demand over 7 days (BOD7) and dissolved oxygen in water (O2). According to the methodology for determining the class of surface water bodies (On surface water..., 2001) and the values of the physico-chemical indicators, the river was found to have: very poor ecological potential in 2021, very poor in 2022, very poor in 2023, poor in 2024, poor in 2025 (according to the Kaisiadorys..., 2024). The worst quality element indicators are oxygen (O2) - 4 mg/l (2024 01), biochemical oxygen demand over 7 days (BOD7) - 8,6 mg/l (2023 05), ammonium nitrogen (NH4) - 2,2 mg/l (2021 01), nitrate nitrogen (NH3 - N) - 3,1 mg/l (2023 02), total nitrogen (Nb) - 13,26 mg/l (2025 01), phosphate phosphorus (PO4-P) - 0,91 mg/l (2022 02) and total phosphorus (Pb) - 1,98 mg/l (2023 04) The analysis of the literature has shown that renaturalisation can be an effective tool to improve the ecological status of a river affected by anthropogenic activities, and the most appropriate renaturalisation measures to improve the ecological status of the water quality have been selected, taking into account the indicators of the Praviena River identified in the studies. It is recommended to take into account the characteristics of the specific stretch of the river and to base the selection of specific solutions, i.e. the detailed design of the restoration measures, on economic and ecological criteria.