Variations of δ18O in Rivers of Crimea in Winter

Abstract

The results of studies of variations of δ¹⁸O values in river water in Crimea Peninsula in January–February 2015–2017 are given. The variation range of δ¹⁸О in river water over the three years of studies never exceeded 3‰. A tendency toward an increase in δ¹⁸О in the water of the Salgir, Kacha, Al’ma, Bel’bek, Biyuk-Karasu from their sources to mouths was identified and explained by a decrease in evaporation in the mouth areas of the rivers relative to their sources and upper reaches, and the inflow of isotopically light precipitation (rain and snow) into the rivers in their upper reaches. The values of δ¹⁸О in waters of the rivers with regulated stream were found to increase under the effect of the Simferopol Reservoir on the Salgir River and the Izobil’nenskoe Reservoir on the Ulu-Zen’ River. The values of δ¹⁸О in the upper reaches of the large rivers of Kacha and Bel’bek (the northwestern slope of the Crimean Mountains) vary from −8.7 to −9.7‰, except for the rivers of Al’ma (−7.7‰) and Kokozka (−10.2‰) because of the different shares of groundwater in the recharge of these rivers.