Análisis de los elementos geomorfológicos fluviales del río Jerte mediante teledetección SAR

Résumé

Strong rainfall events trigger high flooding events, causing catastrophic effects on the environment and human facilities. In order to analyze exposure and vulnerability to flood risk, it is necessary to carry out a multi-temporal evolutionary study of some areas which, due to specific events, cause great material damage and even human losses. Some sectors of the Jerte River (Cáceres, Extremadura) present geomorphological conditions that allow a detailed analysis of the genesis of fluvial landforms (Lombana and Martinez-Graña, 2021), influencing the geodynamic processes of erosion-sedimentation. In this study, we analyze the geomorphological changes on the fluvial system as a consequence of the strong rainfall event occurred on November 21, 2020 around the Jerte Valley. Based on the analysis of SAR images (Sentinel 1), the perimeter and distribution of the water-sheet are delimited during the maximum flood event (Sánchez-Sánchez et al., 2019). Subsequently, the analysis of post-flood Sentinel 2 images allow to identify the morphodynamic changes that occurred in different sectors of the riverbed. As a result, we highlight: (1) modifications in the hydrological connectivity caused by shifting and cutting of river channels, currently abandoned; (2) the increase in the dimensions of the central and lateral river bars due to accretion phenomena and; (3) erosive processes affecting urban infrastructures and facilities.