Трасформаційні процеси у штучних водоймах р. Жванчик та їх моделювання

Abstract

У статті розглянуто особливості трансформаційних процесів штучних водойм у середній течії річки Жванчик та проаналізовано вплив гідротехнічних споруд на морфометричні й гідрологічні параметри водних екосистем. Використовуючи геоінформаційні технології проведено просторово-часовий аналіз змін у межах водозбору, зокрема трансформації берегової лінії, зміни площі водного дзеркала та динаміки замулення. Досліджено гідрохімічний склад води штучних водойм та здійснено інтеграцію польових і дистанційних даних для створення комплексної ГІС-моделі середньої течії р. Жванчик. Результати дослідження дають змогу оцінити сучасний екологічний стан водойм, визначити напрями їхнього сталого використання та розробити рекомендації щодо оптимізації водогосподарської діяльності регіону.

The article examines the specific features of transformation processes in artificial reservoirs within the middle course of the Zhvanchyk River (Khmelnytskyi region) and analyzes the impact of hydraulic structures on the morphometric, hydrological, and hydrochemical parameters of aquatic ecosystems. Geoinformation technologies were applied to conduct a spatiotemporal analysis of changes within the catchment area, allowing the identification of shoreline transformation, variations in the water surface area, sedimentation levels, and changes in the structure of surrounding landscapes. To improve the accuracy of the assessment of reservoir conditions, field observations, remote sensing data, and hydrochemical monitoring results were integrated within a comprehensive GIS model of the middle Zhvanchyk River course. The analysis of major ion composition indicates that, by their chemical type, the waters of artificial reservoirs in the Zhvanchyk River basin belong to the hydrocarbonate–calcium type, with a total mineralization ranging between 380– 500 mg/dm³, which slightly decreases during summer floods. The highest mineralization levels were recorded in the Katsapskyi Pond, whose water area lies within a zone of shallow Cretaceous deposits. During flood periods, a decrease in the concentration of most major ions was observed, except for Ca²⁺, Na⁺ + K⁺, and, in some cases, Clˉ and SO₄²ˉ, which is likely due to the inflow of agricultural runoff, dissolution of gypsum layers, or anthropogenic impacts in the upper reaches of the river. A close correlation was established between arable land cultivation within the surface runoff basin and the hydrochemical composition of the studied reservoirs, most clearly reflected in the content of biogenic substances. During summer floods, a decrease in pH levels was recorded, most likely caused by the inflow of residual mineral fertilizers with surface runoff, particularly ammonium sulfate ((NH₄)₂SO₄). This is indirectly confirmed by the increase in the concentrations of ammonium nitrogen and phosphorus compounds. The excessive input of phosphates and nitrogen compounds is the main factor contributing to eutrophication processes, leading to water “blooming,” reduced transparency, and changes in the biological structure of aquatic masses. Spatial analysis based on GIS modeling revealed a clear relationship between land plowing intensity and the degree of reservoir degradation. A particularly illustrative example is the Sokolyushchynskyi Pond and the stream above it, which formerly contained another water body established in the 1980s. The absence of adequate buffer zones has intensified sedimentation processes, caused the accumulation of biogenic substances, and ultimately led to the near disappearance of the reservoir. These findings confirm that anthropogenic pressure from agricultural land use is a key factor driving the transformation of water bodies in the Zhvanchyk River basin. The constructed geoinformation model made it possible to generalize the obtained data, visualize the dynamics of morphometric and hydrochemical parameters, and propose spatial scenarios for optimizing water management activities. The conducted analysis forms a basis for developing measures aimed at the sustainable use of artificial reservoirs and the preservation of their ecological balance under current climatic and anthropogenic stress conditions.