Drainage morphostructural anomalies of the Rio Salado in Lomadas de Otumpa (Santiago del Estero y Chaco) detected by digital processing

Abstract

Morphology and dynamics of alluvial fan of Río Salado del Norte are studied and presented. The area is located in the Gran Chaco region (provinces of Chaco and Santiago del Estero, Argentina), within the distal piedmont that evolves from the Andean uplift. Through the integration of digital processing optical satellite imagery and digital elevation model (DEM), it is recognized runoff direction, morphology and relative ages of four groups of the associated paleovalleys. It is also performed a drainage characterization from local deviation anomalies and/or changes in the pattern of courses to fit the structure and/or regional topography, particularly in low relief areas. Thus, there is evidence of two important changes in its dynamics, one gradual regional deviation from its main channel to the south, and a local scale feature associated with the uplift of Lomadas of Otumpa. Thus, these detected anomalies or changes in the hydrological regime, where the ancient alluvial fan was changed, interrupt its natural slope gradually to the end, which is now locally invert in the northwest, and diverts the main course southward, where it flows today. The digital mapping, supplemented by geological knowledge of surface and subsurface, it is an irreplaceable tool in morphostructural interpretation of plain areas with little evident relief and contributes to better natural resource management.