Análisis comparativo de los factores determinantes en la susceptibilidad geodinámica de dos microcuencas en el sector Marianza

Abstract

In March 2022, a debris flow in the Sayausí-Cuenca parish caused damage to infrastructure and loss of human lives. This event highlighted the need to understand the contributing factors to its occurrence. This research focused on determining these factors and assessing the susceptibility of two micro-watersheds to debris flow in the Marianza sector. Activities included geological and geomorphological characterization, soil classification, analysis of precipitation, rainfall-runoff modeling, and mapping of debris flow susceptibility using the RES methodology. The results revealed the accumulation of material composed of gravel, sand, and clayey silt in the upper parts of the microwatersheds with a high capacity to flow in a saturated state. The presence of a shallow rocky layer with low permeability and concave surfaces in the upper areas was also identified. Furthermore, there was evidence of loss of vegetative cover and expansion of agricultural activities. March 2022 was the rainiest month in 19 years, with a maximum intensity of 42 mm/h and a return period of 30 years. Rainfall-runoff models indicated flow rates exceeding 250 L/s in the upper parts of the micro-watersheds. This study provided valuable information on the determining factors for debris flow occurrence and the susceptibility of micro-watersheds in the Marianza sector, which could aid in the implementation of prevention and risk management measures in the future. Detailed discussions and conclusions are presented in subsequent sections of this research work.