Features of constituents in the Kuyalnyk estuary groundwater inflow

Abstract

Purpose. To establish current features in the hydrological regime of aquifers and respective constituents of the estuary inflow with groundwater based on many years’ observations in order make the Kuyalnyk Estuary water balance qualitative assessment more precise. Methods. Hydrodynamic methods of groundwater specific discharge calculation depending on spatial and temporal changes of the estuary flow and water level were used. Results. To establish the regularities of groundwater regime in 2015 a network of hydrogeological wells was equipped in the Kuyalnyk Estuary floodplain (villages Kovalivka – Stara Emetivka). It has been established from the results of the observations of 2015 – 2017 that there is the close hydraulic connection between groundwater and surface water of the estuary; it has also been established, that the specific inflow of groundwater from the eastern bank prevail over that from the western bank. Results of calculation of the underflow specific discharge in the upper reaches of the estuary are showing that during dry periods water losses from the estuary to form the reverse direction underflow take place. Specific discharge of groundwater flow from the sea through alluvial deposition of bay-bar was estimated, as well as specific discharge of groundwater flowing from the sides of the estuary valley (aquifers in wind-born and diluvial deposition of middle and upper Pleistocene in interfluvial plain, Kuyalnyk Stage and Pontic horizon). As of 2016 -2017, average annual volume of all the constituents of groundwater inflow to the Kuyalnyk Estuary equaled to 17-20 cm increase of the estuary level and in comparison with the estuary volume in 2016 made around 35 - 50 %. Conclusions. Estimating the Kuyalnyk Estuary water balance, spatial and temporal changes of all constituents of groundwater inflow volume should be taken into account together with the traditional factors of its hydrological regime forming (precipitation, river and side discharge, evaporation).