Ecological assessment and forecasting of surface water conditions in the Dnipro river in Zaporizhzhia

Abstract

Purpose. To provide a comprehensive environmental assessment and forecast of the condition of surface waters of the Dnipro River within the Zaporizhzhia region, with a focus on the dynamics of key water quality indicators during the period 2013–2024. Special attention is given to anthropogenic factors, particularly the consequences of military actions and the destruction of the Kakhovka Hydroelectric Power Plant, which significantly altered the hydrological regime and impacted the ecological balance of the river.

Methods. Systems analysis, statistical data processing methods, distribution analysis, and regression modeling were employed to assess retrospective dynamics and predict future trends.

Results. Long-term monitoring data obtained from the Water Monitoring Laboratory of the Basin Water Resources Department of the Azov Sea Rivers were used. The primary focus was on evaluating six key water quality indicators: phosphates, ammonium, sulfate and chloride ions, biochemical oxygen demand over five days (BOD₅), and dissolved oxygen concentration, to assess the ecological state of the Dnipro River's surface waters in the Zaporizhzhia region, particularly in the drinking water intake area (DVS No. 1) in the upper reservoir of the Dnipro HPP. Phosphate and ammonium concentrations show periodic fluctuations driven by seasonal factors and fertilizer usage. Sulfate levels exhibit high variability of both natural and anthropogenic origin, while chloride concentrations remain relatively stable. Data on dissolved oxygen and BOD₅ indicate seasonal dynamics, which have been disrupted since 2023 due to the destruction of the Kakhovka Dam. The analysis confirmed the river's capacity for partial self-recovery, particularly under reduced anthropogenic pressure during wartime. Regression models were developed for predictive assessment of pollution levels and environmental risks.

Conclusions. The study identified key ecological problems in the Dnipro River, including organic and mineral pollution, disrupted hydrological regimes, and decreased oxygenation. The war-related destruction of hydrotechnical infrastructure exacerbated these issues. Despite this, the river demonstrated resilience through natural self-purification processes, especially as phosphate and ammonium loads declined. Restoration of ecological balance will require systemic monitoring, rehabilitation of water infrastructure, and regulation of pollutant sources. The developed models provide a basis for forecasting and managing surface water quality under both peacetime and post-war recovery scenarios.