ANTHROPOGENIC INFLUENCE UPON THE SUKIL RIVER BED FUNCTIONING

Abstract

A river bed is a main indicator of the changes, including manmade ones that take place in their catchment basins. These changes are reflected in the river beds functioning, especially within the catchment basins located in the Ukrainian Carpathians. These basins have been noticeably affected by human impact during last century. The Sukil River (left tributary of the Svicha River) is one of them. By the relief morphology features and geologic-geomorphologic structure the Sukil River basin is divided into three parts: mountain, premountain and plain. The river bed within these three parts is characterized by noticeable difference in morphological and morphodynamical parameters. And the reaction of the riverbed on the manmade changes also is different in all three parts. First of all, it is a deforestation, agriculture, unauthorized gravel intake within the river bed and floodplain, river bed straightening, river bank consolidation and flood protection dikes constructing, melioration and ponds constructing etc. Research results ascertained noticeable difference between manmade influences in different parts of the catchment basin, especially the effects on the river beds and their functioning. In the mountain part the moderate impact dominates and is mainly presented by timber falling which has caused significant sediments runoff increasing during the floods of 2008 and 2010. In the premountain part the strongest impact is done by the unauthorized alluvium mining in the river bed. It caused increasing in the river bed morphodynamics and reinforcing of the linear and local side erosion. The erosion processes threat the roads and buildings within the river valley. The plain part of the river basin is most transformed. The river bed strengthening is carried out since the middle of ХХ-th century which was accompanied by the dikes and drainage network constructing. As the result many boggy areas were drained, the morphology of the Sukil river bed was changed, the meander process was stopped. But the tendencies to renaturalization of the river valley are observed during the last years. Conducted research are important for the rivers renaturalization and providing the strategy of sustainable development in Ukraine in the matter of natural resources protection and management. Key words: channel morphodynamics; Sukil River; anthropogenic influence; mountain, premountain and plain parts of the basin.