CYCLIC FLUCTUATIONS OF THE AVERAGE ANNUAL EXPENDITURES OF THE STOKHID RIVER (RIGHT TRIBUTARY OF THE PRIPYAT)

Abstract

The article is devoted to elucidating the closeness of the relationship between the average annual flows of the Stokhid River (hydrostations Malynivka and Lyubeshiv) and precipitation (according to the Lutsk and Lyubeshiv weather stations), analyzing the cyclicity of fluctuations of these hydrometeorological characteristics over a half-century period (1972−2021). In the course of the research, the authors revealed trends in the multiyear dynamics of the average annual flow of the Stokhid River at the Lyubeshiv and Malynyvka hydrostations during this period; the closeness of the relationship between river flow and atmospheric precipitation during this time was determined; the duration and nature of the alternation of increasing and decreasing phases of multi-year fluctuations in annual amounts of precipitation and average annual water consumption of the river were analyzed; the synchronicity (asynchrony) and synchrony (asynchrony) of the fluctuations of these hydrometeorological indicators were estimated; an attempt was made to predict the water level of the river in the coming years, based on the drawing of the difference integral curves and the determined duration of the phases of fluctuations of the river's water flow. Graphic constructions and the results of the calculations show that in the upper course of the river, the dependence of water flow on precipitation is higher than in the lower course. During 1972−2021, two incomplete cycles of fluctuations in annual amounts of precipitation and average annual costs are traced at both hydrostations of the Stokhid River. At the same time, there is a noticeable shift in the phases of fluctuations in the average annual flow of river water relative to the phases of precipitation fluctuations with a shift of one calendar year. During the entire research period, fluctuations in the average annual flow of the Stokhid River were synchronous and in phase at both hydrostations. The asymmetry of fluctuations of hydrometeorological indicators was traced at the Lyubeshiv hydrostation (lower stream) during 1988−1994, which could probably be connected with the beginning of the period of modern climatic changes in the territory of Ukraine, the starting point of which is considered by most scientists to be 1989, and the influence of the the end of the 20th century remedial measures. Under the condition of preservation of the climatic trends found in the region and the relative stability of the existing anthropogenic load in the river basin, the drawing of the constructed differential integral curves allows predicting the further decline of the Stohod water level until approximately 2030.