Water Balance of Crimea for 2001–2021 by Ground-Based and Remote-Sensing Data

Estimates of precipitation, evaporation, river runoff, potential evaporation, and components of basin water reserves were obtained for the territories of Crimea and/or several its river basins. The period of 2014–2021 was characterized by higher aridity than 2001–2013, as can be seen from a decrease in precipitation and river runoff and an increase in the evaporation depth. The balance of the channel flow tends to decrease from the upper parts of the basin to its lower parts. The only exception is the Belbek River basin, where runoff losses are concentrated in the middle part of the drainage area. The analysis of changes of the measured and climatic runoff over the two periods showed an increase in runoff losses not associated with evaporation in many mountain and piedmont areas, which is likely due to a decrease in groundwater inflow and an increase in water intake. It is possible that in the lowland parts of the catchment areas of the Alma, Chernaya, Belbek, and Kacha, as well as the upper reaches of the Salgir, the river runoff increased due to groundwater extraction and the further release of wastewater into the rivers. The decrease in runoff in the Salgir basin by 0–40 mm can be partly explained by the closure of the North Crimean Canal in 2014. The decrease in groundwater reserves in Crimea over 2003–2020 was estimated at about 150 mm.