Geología · 2026

Estimación del aporte de sedimentos por movimientos en masa a la avenida torrencial ocurrida en Cerro Bravo, cuenca de la Quebrada La Tigra, Municipio de Venecia, Antioquia

Torrential flows are phenomena associated with the mobilization of water and sediments from unstable slopes, capable of transporting between 20% and 60% solid material by volume at velocities of up to 30 m/s. These events rank among the natural hazards with the shortest warning times and the highest human and material toll in Colombia. Despite their recurrence, the sediment contribution from mass movements is commonly assumed as a fixed value of 40%, which may introduce considerable uncertainty in hazard assessment. This study aimed to estimate the actual volumetric proportion of sediments contributed by mass movements to the torrential flow that occurred on June 25, 2024, in the municipality of Venecia, Antioquia, Cerro Bravo area, specifically in the La Tigra stream basin. The methodology included photointerpretation of orthophotos, an inventory of mass movements, and the delineation of material detachment and accumulation zones. A pre-event Digital Elevation Model (DEM) was generated, from which the volumes of mobilized sediments and their contribution to the event were estimated through DEM differencing analysis. The results show that approximately 34.3% of the total volume of the torrential flow corresponds to sediments supplied by mass movements. These results contribute to a better understanding of torrential flow dynamics and provide relevant information for hazard assessment as a function of sediment concentration.

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