The Main Features of Transformed Seawater Penetration in the Dniester River Mouth at Surges Caused by Storm Winds

Abstract

Abstract The article considers the possibility of brackish water rising from the Dniester Estuary up the Dniester River mouth, where Station “Dniester” supplies potable water to Odesa City and the intake point of the Lower Dniester Irrigation System is located. The study is topical as the brackish water threatens the quality of drinking and irrigation water at the intake waters. The purpose of the work has been to use hydrodynamic modelling to establish the hydro-meteorological conditions under which the transformed sea water from the Dniester Estuary could enter the mouth part of the Dniester. It has been established that the following conditions are to be met for the transformed marine water to rise into the estuarine arms of the Dniester River: (1) average daily river discharge decrease below 100 m3/sec; (2) domination of surge wind from south or south-east at a speed exceeding 15 m/sec for several days. Under such conditions, the transformed marine water rises from the estuary upstream into the Dniester River mouth through the right arm, the Glybokyi Turunchuk, and then, having reached the place where the main river channel divides into two arms, the estuarine water is driven into the left arm - the Dniester and, by it comes back to the estuary. The case described in the article could be used by experts as an example when identifying effective hydro-engineering measures to prevent transformed sea water penetration in river mouth by building a second estuarine canal (branch).