Features of the hydrological regime and channel processes of the Dereluy River (based on field research data)

The problem of studying channel processes on small rivers of the Precarpathian region lies primarily in the insufficient amount of information due to the lack of regular observation data. The insufficient amount of materials on the hydrological regime and the nature of channel processes on small rivers is always objectively justified by the lack of stationary monitoring points. That is why, to determine the nature of channel processes on small rivers, the most optimal method of research today remains the expeditionary method, which provides for direct examination of the channel in key areas, relevant measurement work, GPS surveying of banks and the possibility of visual assessment of the condition of the channel and sediments at individual points. All this allows us to take a somewhat more detailed and constructive approach to determining and assessing the nature of channel processes on small rivers. The purpose of this study was to conduct a preliminary assessment and analysis of the hydrological regime and bed-forming factors of the Dereluy River. Such an assessment is based on many methods of geographical research, but when it comes to determining the types of bed of specific sections of rivers, the most successful are the combination of cartographic and expeditionary methods. Thanks to the cartographic method, it is possible to assess the configuration and condition of the hydro network of the studied object, and even trace their changes by comparing maps of different periods. It should be noted that to assess the condition of the hydro network, we used topographic maps of 1:100,000 for the territory of the basin in 2006 and maps of the Austrian period with a scale of 1:250,000. However, as many years of experience show, for small rivers the expeditionary method is quite representative: with a visual inspection of the bed in separate sections, according to the conditions, and the selection of key points for in-depth analysis using instrumental surveying. It was precisely such a trip that took place in the fall of 2025, the results of which will be presented in this publication. The results obtained provide starting material for further in-depth study of the features of channel processes on the rivers of the studied basin, thanks to cross-sections it is possible to calculate the channel-forming water flows at given speeds and water levels, and repeated leveling after a certain period of time will allow to estimate the intensity of vertical and planar deformations in the surveyed areas. Also, based on the results obtained, it became possible to determine the flooding zones during high floods even in the absence of regular observations at the research object and to estimate the stability coefficient of the river channel by mathematical (calculation) methods