Modelling Water Erosion and Mass Movements (Wet) by Using GIS-Based Multi-Hazard Susceptibility Assessment Approaches: A Case Study-Kratovska Reka Catchment (North Macedonia)

Kratovska Reka is a short (17.3 km) left tributary of Kriva Reka, whose watershed (68.5 km(2)) is located on the northwestern slopes of the Osogovo Mountains (North Macedonia). Due to the favorable natural conditions and anthropogenic factors, the Kratovska Reka catchment is under a high risk of natural hazards, especially water erosion and landslide occurrences. For this reason, the paper presents an approach of modelling of potential erosion and areas susceptible to the above-mentioned hydro-meteorological hazards in the Kratovska River catchment. Firstly, this study analyzed the main geographical features that contribute to intensive erosion processes in the area. Then, using the Gavrilovic EPM erosion potential method, an average value of 0.56 was obtained for the erosion coefficient Z, indicating areas prone to high erosion risk. Furthermore, by using landslide susceptibility analysis (LSA), terrains susceptible to landslides were identified. The results shows that 1/3 of the catchment is very susceptible to mass movements in wet conditions (landslides). According to the combined multi-hazard model, 3.13% of the total area of the Kratovska River catchment is both at high risk of landslides and under severe erosion. The Kratovska River catchment is significantly endangered by the excessive water erosion processes (39.86%), especially on the steep valley sides, i.e., terrains that are completely exposed, under sparse vegetation, and open to the effects of distribution/concentration of the rainfall amounts throughout the year. Identifying locations with the highest erosion risk serves as the initial step in defining and implementing appropriate mitigation measures across local and regional scales, thus enhancing overall resilience to environmental challenges.