Cloud-Based Mapping of Soil Erosion Susceptibility for Catchment Prioritisation in the Western Balkans Using a Modified Erosion Potential Method

Soil erosion is recognised as one of the most pervasive forms of land degradation across the Western Balkans (WB), a 208,052 km2 region for which its erodible substrates, contrasting climates, and long history of land-use pressure produce highly variable erosion regimes. This study delivers the first regional-scale assessment of soil erosion susceptibility for the entire WB through a cloud-based implementation of a modified Erosion Potential Method (EPM) in Google Earth Engine (GEE). The computation was performed at 30 m resolution and aggregated across 9524 catchments derived from the EU-Hydro database, with the dimensionless erosion coefficient (Z) serving as the primary susceptibility metric. The modelled patterns reveal a strong north–south asymmetry in erosion intensity: The highest country-level coefficients were obtained for Albania (0.47), North Macedonia (0.38) and Montenegro (0.37), while Serbia (0.29) and Bosnia and Herzegovina (0.28) recorded lower regional means. About 19.8% of the WB area falls within catchments classified as highly to very highly susceptible, with such basins concentrated along the Adriatic-facing mountain front and across the Aegean headwaters. Validation was carried out at three complementary levels, including point-based statistical validation on 1379 field- and orthophoto-verified points distributed across the WB, which yielded an AUC = 0.828. Although the proposed framework should not be considered a substitute for fine-scale, field-based modelling, it provides a transparent, reproducible, and scalable basis for regional screening, catchment prioritisation, and the design of soil-conservation and land-management interventions across the WB.