Pylypiuk V. Hydrological - hydrochemical characteristics and water quality of the Psel and Vorskla rivers.

The Dissertation shows the basics of theoretical and applicational principles of the changes in hydrological, hydro-chemical and hydroecological regimes of the rivers under conditions of climate change, when the water content of the rivers decreases and anthropogenic ifluence on water resources increases. The analysis is perfomed as well as evaluation of the changes for climate factors and outflow characteristics (annual, maximum, minimum, underground), which occurred in the past two decades. To assess the water resources of the rivers that are researched there was chosen selected model "climate-outflow" based on the meteorological data.Main tendencies of the water resourses changes in the XXI century are revealed with apply of the data in the calculations of climate scenarios. The research of the changes of the hydrochemical characteristics is performed as well as complex index of the water quality by time and by length of the river. The major sources of contamination and the major pollutants that lead to the deterioration of the ecological state of the rivers are established. Influence of abiotic factors on hydrochemical and hydroecological state of rivers under the conditions of climate change is described. The methodological approaches to the calculation of concentrations of pollutants along the length of the river is presented. Which are based on their natural purification during the process of water lag from the upper to the lower cross-section.