Impact of climate change on the hydrological regime of the catchment and environmental safety of the Dnipro tailings dump

The article describes the hydrographic network on the territory of the Dniprovske tailings dump (Kamianske, Ukraine). The article highlights the changes that have occurred over the 150-year history of the Dnipro River section between the settlements of Kamianske and Taromske, where 12 million tonnes of radioactive waste (RW) are currently stored in the Dnipro and Konoplyanka rivers at the site of buried rivers (Khreshchatka, Zhovtukha, Borziyka). To assess meteorological and climatic data, statistical methods of their generalization and comparison with the data of the Climate Reference Books were used. It has been established that over the past 17 years (2005-2021) of observations, the average annual air temperature in the region, according to the data of reference weather stations, has increased by at least 20°C. Over the same period, evaporation from the water surface has also increased. The total amount of precipitation per year in the study area has not changed significantly. At the same time, uneven and spotty precipitation and a more intense nature of precipitation (showers) are noted. The daily amount of precipitation in the Dnipro region is also highly variable, even for the autumn-winter period, when there is a siege precipitation covering large areas. The observed peculiarity of the absence of permanent snow cover in winter in recent years contributes to an increase in the frequency of freeze-thaw cycles, and in summer, due to an increase in the intensity and magnitude of storm rains, deep soaking, which negatively affects the structure and integrity of the cover rocks (phosphogypsum) and protective dams of the radioactive waste tailing pond. Intensification of filtration flows through the containment dams and the tailing pit bottom leads to the removal of radioactive substances and increases the environmental risk of surface and groundwater contamination. Probable maximum flow rates and volumes of maximum rain floodwaters were estimated for their organized removal and prevention of filtration into the tailing pit and subsequent migration to the Dnipro River bed. It is proposed to install an impervious cover and engineering measures to improve the regulation of humidity in this area and drain excess water from floods and floods. Recommendations to improve the environmental safety of the tailings dump were developed and substantiated.