Research on the topic of the dissertation was performed during 2015–2018 according to the research plans of the Department of Constructive Geography and Cartography of the Faculty of Geography of Ivan Franko National University of Lviv and the Department of Physical Geography and Efficient Environmental Management of the Faculty of Geography of Uzhhorod National University.
Based on the work of Khilchevsky V. K., Kovalchuk I. P., Boyarin M. V., Karaushev A. V. and others, as well as the Water Framework Directive of the EU 2000/60/ EU, the hydroecological status of river waters is considered with the help hydrological, hydrochemical and physical parameters of the regime and quality of water within a single line, point or section of the river for a certain period (season, year, perennial period).
The dissertation research was conducted on the basis of the materials of observations of the Transcarpathian Hydrometeorological Center, the Basin Department of Water Resources of the Tisza River and the State Ecological Inspectorate in the Transcarpathian Region, as well as literary sources on the research topic, empirical data of expeditionary research carried out by the aspirant in the period from 2015 to 2018, data of hydrochemical analyzes of selected water samples, topographic maps at a scale of 1:25 000 and space images using Google Earth Pro. To perform the graphic part of the work, the aspirant used ArcGIS software 10.4.1. and Microsoft Excel. Methods for assessing water quality according to the hydrochemical index of water pollution (IWP), integrated ecological indices (IE), as well as the methodology proposed by the International Commission for the Protection of the Danube River (ICPDR) were used.
The influence of natural and anthropogenic factors on the formation of hydroecological conditions of the Tisza River and its tributaries within the Rakhiv District has been determined. The influence of the geological structure of the basin, water content, the amount of precipitation, different types of anthropogenic load on the hydrogen index pH, dissolved oxygen content, overall mineralization, content of major ions, nutrients, heavy metals and specific toxic pollutants in the waters of the Tisza River and its tributaries has been studied in detail. Particular emphasis is placed on the seasonal variability of the abovementioned indicators. Changes in the hydroecological conditions of the Tisza River basin under the influence of economic activity, in particular, tourism and recreation, agriculture, industry and municipal sector have been analyzed.
According to the data of water quality monitoring and hydrochemical surveys carried out by the aspirant, IWP for the period 1994–2018 have been calculated; they vary in the range of 0.19–0.93 and correspond to the 1st (very pure water) and the 2nd (pure water) water quality classes. Integrated ecological indices (IE) of waters of the Tisza River basin during 1994–2018 changed in the range of 1.6–2.6 and also correspond to the 1st (excellent ecological condition) and the 2nd (good ecological condition) water quality classes. According to the methodology proposed by the International Commission for the Protection of the Danube River, the Tisza River waters studied during 2006–2018. At the monitoring points of the Tisza River (the village of Dilove) during 2008–2014 and the Tisza River (the village of Velykyi Bychkiv) during 2006–2018, according to the requirements of the methodology proposed by the International Commission for the Protection of the Danube River, the 2nd (pure water) and the 3rd water quality classes (conditionally pure water) was recorded. The satisfactory ecological condition of the waters of the Tisza River was determined by the worst indicators of copper (Cu) and zinc (Zn).
Based on the study, the importance of expanding the network of water quality monitoring points within the studied part of the Tisza River basin, in particular on the rivers the Black Tisza, the White Tisza, the Shopurka, and the Kosivska, is substantiated. Measures have been proposed to optimize the nature management, which will allow to achieve a good ecological condition of the waters of the Tisza River basin within the Rakhiv District of the Transcarpathian Region.
Key words: hydrochemical regime, hydroecological conditions, influencing factors, water consumption, water pollution, water quality class, optimization of nature management.
