Debris-Flow Susceptibility Assessment in a Semi-Arid Mountain Belt: Western Taurus, Turkiye

Debris flows are a significant geohazard in the semi-arid mountain belts of southwestern Türkiye, where short-duration, high-intensity rainfall frequently triggers rapid sediment mobilization, generating destructive debris-flow hazards that threaten settlements, transportation corridors, and agricultural land. The catastrophic 6-7 August 2018 debris-flow event, reported to have caused severe damage to agricultural fields, livestock, and road infrastructure (in both two villages, one day apart) together with more recent rainfall-triggered events in the area, highlights the vulnerability of the region; since these basins drain into the Elmalı polye, a critical agricultural hub, assessing debris-flow susceptibility is essential for future risk mitigation. This study presents a regional debris-flow susceptibility assessment for the Elmalı Basin (Western Taurus Mountains) in Antalya, Türkiye. Using a 5m resolution DEM, NDVI-based vegetation change analyses, topographic thresholds (slope, curvature, flow accumulation), and lithological data, potential source areas were identified, and runout paths were modeled with the empirical Flow-R approach. Model calibration was supported by geomorphic evidence of the 2018 event, and NDVI difference maps provided an effective tool for evaluating the accuracy of runout angle calculations. The results highlight several channels where steep, concave slopes coincide with high-susceptibility zones, indicating that certain settlements and agricultural fields lie within potential impact zones.