АУТОР / AUTHOR(S): Ilia Tamburadzhiev 
DOI: 10.46793/CSGE5.23IT
САЖЕТАК / ABSTRACT:
The present study is focused on remote sensing data analysis of the factors for formation and development of debris flows in various mountain drainage basins in Bulgaria. The extent of susceptibility to the formation and development of debris flows in the range of selected mountain key sections of the drainage basins was investigated and a risk assessment was carried out. The relevance of the present study is related to the frequency of adverse hydro-climatic phenomena of natural and anthropogenic origin in the last decade in different parts of Bulgaria—Asparuhovo (2014), Karlovo (2022), Berkovitsa (2023), Tsarevo (2023), etc. Similar events cause lasting damage to infrastructure, economy, and public life, and sometimes lead to human casualties.
The role of geological-geomorphological factors, water runoff, and land cover was studied. A morphometric analysis of the relief was carried out in order to obtain specific values of the morphometric characteristics of the drainage basins and the channel networks. To achieve the goal of the study, an analysis and synthesis of scientific literature on risk, hydro-climatic, and geomorphological phenomena in the studied drainage basins was carried out.
GIS methods were used to calculate morphometric indicators/parameters (such as area, perimeter, length and width of the drainage basin, hypsometric integral, Melton ratio, total length of the river network (km), total number of tributaries (N), circularity ratio, bifurcation ratio, density of the river network (km/km2), frequency of streams (count/km2), etc.) and for calculation of the Normalized Difference Vegetation Index (NDVI). Hydrological modeling was carried out in order to extract the channel networks. The channel networks were classified by stream ordering.
GIS analysis is done on the basis of SRTM Digital Elevation Model (DEM), Landsat multispectral satellite images, topographic maps, geological map, etc. Mapping and risk assessment of debris flows has been carried out which is a first step in disaster risk reduction and management.
КЉУЧНЕ РЕЧИ / KEYWORDS:
debris flow; morphometric analysis; drainage basin; risk assessment; remote sensing