Current morphological and hydroecological characteristics of the Berezan river

Abstract

The article presents the results of two-year ecological, hydrological and hydrochemical studies of Berezan, one of the steppe rivers of Mykolaiv region, which begins the Berezan estuary in the lower part of the Tyligulo-Buzka confluence. The current state of the Berezan River is characterized by a significant level of anthropogenic transformation of the watercourse associated with the construction of cascade ponds. The independent existence of the flow rate and yearround water content of the Berezan River without its support by technical means of water supply is impossible. According to the hydrochemical composition of the river water, it belongs to the bicarbonate-calcium type with a high content of sulfates, chlorides, and sodium, differing in an extremely dynamic level of mineralization — from 760 mg/dm3 during the flood to 2900 mg/dm3 during the low tide. No less active influence on the state of this small steppe river and the Berezan estuary initiated by it are also exerted by natural factors such as increasing aridity of the climate, transgressive tendencies of the Black Sea, increasing environmental temperatures, increasing evaporation volumes and changes in the balance of surface-underground water exchange. Because of this, the Berezan River today is no longer able to independently maintain the water content, flowability and stability of the hydrochemical regime, showing a tendency to transform into a seasonally draining network of streams. The current nature of the water filling of the river is ensured by a cascade of reservoirs and maintenance of the flow rate due to water discharges from the South-Bug irrigation system fed from the South Bug. Despite the hydro-ecological problems, the river is still an important draining watercourse of the Tiligulo-Buzka interfluve, providing drainage, water regulation of the area and replenishment of underground horizons, with which the drinking water supply of 19 settlements is connected.