Pavelchuk Y. The features of hydrological and hydrochemical regime of the rivers of Zhytomyr Woodlands in the conditions of climate changing.

The thesis is devoted to the research of features of modern hydrological and hydrochemical regimes of the rivers of Zhytomyr Woodlands in the conditions of climate changing. Including the current data of hydrological observation, a phase-cyclic structure of perennial fluctuations of water flow of the rivers of Zhytomyr Woodlands during the period from 1925 till 2012 is investigated, statistical parameters of variation series of the water flow are calculated and long-term flow standards are specified. For the verification of the hypothesis about breaking the stationarity of the water flow in the conditions of climate changing, its long-term tendencies were investigated by the method of building the time linear trends and evaluation acording to the criterions of Mann-Kendall. The seasonal and perennial features of hydrochemical regime of the rivers are investigated, evaluation of influence of anthropogenic sources on the formation and dynamics of the contents of pollutants in the river water is made. Statistical modeling of dependence of the contents of dissolved substances in the water and the quantity of water flow is accomplished, graph-analytic method of presentation of hydrochemical regime options in the wide range of real sizes of water flow are proposed in the way of constructing semi-empirical graphical models. The forecast of changing of the water flow of the rivers for the XXI century is done on the basis of water - balance modeling and the results of the modeling of the climate conditions of Ukraine. The possibility of changes of the chemical composition of the river water including the results of long-term hydrological forecast are evaluated.