Просторове моделювання локальних малюнків гідромережі річки Смотрич як індикатора геоморфологічних процесів

Abstract

Проаналізовано просторову структуру гідромережі річки Смотрич з метою ідентифікації напрямів геоморфологічних процесів для потреб збалансованого природокористування. Досліджено вплив тектонічних рухів, розломів та реліктового рельєфу на формування локальних малюнків гідромережі, таких як деревоподібний, радіальний, кільцевий та паралельний. Виділено 10 локацій відцентрового малюнка, що безпосередньо вказують на локальні підняття, та проаналізовано зони активних річкових перехватів із басейнами Південного Бугу, Мукші, Жванчика тощо. За просторовими особливостями малюнків гідромережі територію басейну Смотрича районовано на 5 специфічних ділянок: нижньої течії, товтрову, середньої течії, верхньої течії та верхів’я. Встановлено 4 етапи формування гідромережі у тісному взаємозв'язку з регресивною ерозією та розвитком долини річки Дністер — від межі нижнього та середнього плейстоцену до голоцену. Спрогнозовано подальший розвиток ерозійних процесів, яроутворення, поглиблення русел та формування нових перехватів, що має вагоме практичне значення для розробки довгострокових прогнозів стану водних об’єктів та регіонального моніторингу.

The presented article is devoted to the comprehensive spatial modeling of local drainage patterns within the Smotrych River hydrographic network, utilizing these patterns as precise indicators of active and historical geomorphological processes. Forecasting hydrological dynamics in the watercourses of the Podolian region requires the continuous development and refinement of monitoring methodologies. The drainage pattern serves as a direct manifestation of geomorphological evolution; therefore, employing a spatial model that integrates typical patterns and reflects the geographical conditions of the territory allows for the reconstruction of past developmental stages and the automated prediction of future environmental changes. The primary aim of this research is to identify the underlying trends of geomorphological processes in the Smotrych River basin to facilitate balanced nature management and sustainable regional planning. The Smotrych River, a typical left-bank tributary of the Dniester River located within the Podolian Upland, exhibits active erosional processes, including the continuous deepening of existing channels and the active development of new gullies and ravines. Furthermore, the basin is characterized by pronounced river captures involving neighboring river networks. The foundational tectonic structure of the studied territory is determined by its position on the southwestern periphery of the East European Platform, specifically within the Podolian Precambrian transverse uplift. The spatial variations in the hydrographic network are primarily dictated by a complex system of faults and fractures. Ancient faults, such as the Antopil fault, dictate the axial alignment of the main river, while younger faults, like the Tovtry fault, divide the territory into distinct structural blocks—a lowered southern part and an uplifted northern part. Through detailed spatial analysis, the study identifies the direct influence of tectonic movements on the formation of radial and annular drainage patterns. The authors analyzed ten specific locations exhibiting centrifugal patterns, which directly indicate localized tectonic uplifts. Uneven channel drops in these zones highlight ongoing competition for catchment areas, with the Smotrych network actively expanding at the expense of neighboring basins in certain locations. An explicit annular pattern was identified in the headwaters of the Trostianets River tributaries, corresponding to a local tectonic uplift. Relief and lithology act as equally critical factors in the basin's formation. The alternation of plains and remnant ridges results in parallel and dendritic network configurations. The defining role of relief is particularly evident in the Tovtry zone of the basin, where the relict relief of the main and lateral reef ridges has led to the formation of closed basins and sub-annular channel configurations, often forming an "atoll trap". Additionally, lithological transitions, such as the river reaching Paleozoic sedimentary surfaces or Silurian deposits, trigger the formation of waterfalls, swampy floodplains, and deeply incised omego-shaped meanders along ancient faults. Active zones of river captures are traced throughout the basin, being most pronounced in the northern section and the peripheries of the middle and upper courses. The study documents the capture of the Southern Bug basin, evidenced by the sub-latitudinal orientation of the Smotrych headwaters. Well-defined captures of the Muksha River headwaters by the Chornyvodka and Dvoyatynka tributaries are also analyzed, alongside captures of the Zhvanchyk River headwaters by the Skvyla and Soroka rivers. Based on the distinct variations in regional drainage patterns, the researchers divided the Smotrych basin into five specific geomorphological zones: the lower course (characterized by high asymmetry and waterfalls), the Tovtry zone (featuring a reverse-symmetric pattern restricted by ridges), the middle course (highly asymmetric with large parallel tributaries like Yaromyrka on the right bank), the upper course (displaying a symmetric dendritic pattern up to 40 km wide), and the headwaters (characterized by a straight, sub-latitudinal main channel with pronounced capture hooks). Finally, the spatial structure analysis enables the identification of four distinct evolutionary stages of the hydrographic network, deeply connected to the regressive erosion of the Dniester River valley: the boundary of the Early and Middle Pleistocene, the Middle Pleistocene, the Late Pleistocene, and the Holocene. The study concludes that the deepening of main and tributary channels is ongoing. Anthropogenic factors, such as deforestation on watershed remnants, land reclamation, and the destruction of artificial reservoir dams, actively accelerate linear erosion, gully formation, and new river captures. The developed spatial models provide a crucial foundation for the long-term forecasting of regional water bodies and the mitigation of destructive anthropogenic impacts.