A study of significant factors affecting the quality of water in the Oskil river (Ukraine)

The study has explored climate shifts in the Kharkiv region and changes in the hydrological indices of the Oskil river in Ukraine. Predictive models were constructed by the Holt­Winters method. The findings show an expected gradual increase in temperature by 1.9 °C – from 7.8 °C to 9.7 °C – in 2020, which can lead to a decrease in precipitation, the runoff volume, and water consumption. It also has a significant adverse impact on the formation of surface water quality and on the development of infestations. Natural and anthropogenic factors that have the most significant effects on the hydrochemical characteristics of the Oskil river were specified by a multivariate correlation and regression analysis. The research findings show that the quality of aquatic sites is most affected by wastewater discharges and an increase in air temperature, which testifies to the need of reducing loads from industrial facilities and utilities. The study takes into account landscape and environmental characteristics of the river basin. We have assessed rationality of using the basin catchment area on the basis of exponents such as tillage, urbanization, the volume of water consumption, forest cover, meadow cover, lake cover, and changes in the hydrological characteristics that influence the development of the intensity of degradation processes. The assessment of the processes of ravine formation, land erodibility, silting and waterlogging of small rivers in the Oskil river basin has shown a significant increase in the intensity of the degradation processes compared to 1990, which requires applying environmental protection measures to improve the situation. The ranking of the small rivers in the Oskil river basin by the index of process development helps prioritize the funding of environmental protection measures.