Geomorphological dynamics and human interactions in a semiarid valley in Northwestern Argentina: The Cafayate depression (Salta Province)

Abstract

The aim of this study was to record the changes in the Cafayate region, Northwestern Argentina, over the last 50 years (1969–2019), with a focus on fluvial and dune systems, together with human activity. The multi-temporal analysis of different kinds of remote sensor images and field surveys allowed us to establish that the final section of the Santa María River shows a meandering channel whose arrangement and morphology have substantially changed since 1969. The Santa María River has moved from a northern position in 1969 to the current location, giving rise to a shortening in the channel length from 11756 m to 8217 m, increasing its gradient from 0.10% (1969) to 0.14% (2019), with its sinuosity index falling from 2.85 to 2, although the lateral erosion of the channel and the meanders have remained very active. The floodplain supplies sands to feed the aeolian dynamics through a close cycle that favors the development of large dune fields, especially in the river stretches where there is transversal wind direction. Moreover, the changes in land use have negatively impacted on the fluvio-aeolian dynamics of the system.