MONITORING OF HYDROCHEMICAL TRANSFORMATIONS ON THE DON SEASHORE IN REAL TIME

The dynamics of the types of waters chemical composition under conditions of frequent alternations of high and low water levels has been studied in the current work. A classification of the characteristic chemical composition under different hydrological regimes (positive and negative water setups) has been constructed. The work is based on monitoring data of the hydrometeorological situation in the Lower Don. The paper presents new results of an investigation of changes in the hydrochemical regime of the Don Delta under conditions of climate aridization. The dynamics of changes in the characteristic types of mineralization during rapid changes in water level was revealed. The main types distinguished by anions were marked: ground type of mineralization (SO42− more than 70%, total salt content 5‒7 g/l), marine (Cl− 70‒80%, total salt content up to 8 g/l) and Don (30‒40% HCO3− ions, mineralization reduced to 1‒1.5 g/l). During alternating series of positive and negative water setups, mixed waters are formed: with increased proportions of chlorides with the dominance of groundwater during negative setup after positive, as well as hydrocarbonates in conditions of groundwater desalination when the water level rises after extreme negative water setup. The abnormal Don lack of water leads to the formation of previously unknown geochemical dependencies in different parts of the basin. A more extensive monitoring network in the delta is necessary, because it is not known how salinization of the basin manifests itself in the areas of water intake for urban water supply. The restoration of the lost network of hydrometeorological stations will make it possible to adapt to the shortage of water resources, as well as to obtain reasonable recommendations for nature management in modern conditions.

Don delta, lack of water, climate change, ionic composition of waters, positive and negative water setups, underground runoff