Multidimensional system geomonitoring of groundwater in water in-takes areas (on the example of Poltava city). Part 1. Identification of system development of hydrogeological process

Abstract

Formulation of the problem. The paper is the beginning of scientific papers series of authors on an actual environmental topic – multidimensional system geomonitoring of groundwater in water intakes areas. The purpose of article is a substantiation of application possibility of the method of objects trajectory modeling in the normalized phase space, which has been developed at V. N. Karazin Kharkiv National University for socio-geographical monitoring tasks, for hydrogeological objects geomonitoring. Materials and methods. The research is based on the method of objects trajectory modeling in the normalized phase space. To achieve the purpose of this study, geomonitoring data of five water intakes in Poltava city, which operate Cenomanian-Lower Cretaceous aquifer, has been used. Changes in the average chemical composition of groundwater for each water intake have been analyzed according to 12 indicators: pH, hardness, dry residue, ammonium, fluorine, chlorine, sulfates, bicarbonates, calcium, magnesium, sodium+potassium, ferrous iron. The initial data have been collected from 1981 to 2008 according to an irregular pattern in time (39 points in time). Research results. The following indicators of systemic development of hydrogeological system have been calculated for each water intake: a) for each period of time – the path length traveled by the water intake hydrogeological system, which characterizes the intensity of changes in the groundwater chemical composition; b) for each control time – the projection of current trajectory point on the optimal trajectory (main diagonal), the deviation of point from the optimal trajectory, the progress coefficient (the ratio of point projection to the length of main diagonal). The main trends in the systemic development of hydrogeological system for all studied water intakes have been identified: - the intensity of changes in the groundwater chemical composition at water intakes Nos. 1-5 decreases over time, which can be explained by the reduction of water withdrawal and hydrodynamic factors associated with the formation of depression funnel, in particular the spreading of quasi-stationary filtration regime; - according to the absolute values of changes intensity in the groundwater chemical composition, the water intake No. 3 is highlighted, the value of which is significantly less than the values of other water intakes; - groundwater at the water intake No. 1 has the greatest variability in the changes intensity of chemical composition over time both in amplitude and in absolute values; - there is a very noticeable synchronization of movement intensity graphs of water intakes hydrogeological systems in the normalized phase space and the average intensity of changes in the groundwater chemical composition, but a detailed analysis reveals some deviations from this pattern, which may be due to abrupt changes in operation mode of water intakes.