Landslides dams induced by debris flows in quebrada del toro (province of Salta, Argentina)

Authors

  • C. Cencetti Università degli studi di Perugia, Italy
  • F.R. Rivelli Escuela de Geologia, Universidad Nacional de Salta - Bolivia, Argentina

DOI:

https://doi.org/10.4408/IJEGE.2011-03.B-070

Keywords:

Argentina, debris flows, risk

Abstract

The Quebrada del Toro is the valley of Río Toro, located southwest of Salta City, in northwestern Argentina. During the summer months, in the catchment of its tributaries, debris flows occur with relative frequency. Such processes of mass transport bring important volumes of materials inside of the main collector (Río Toro) and its alluvial plain, and they produce the narrowing, or sometimes the occlusion (landslide dam) of the main riverbed. These processes frequently occur, for example, in the Río Candado, a tributary on the left of the Río Toro. The consequence is an important sediment supply, coming from such a tributary, which has produced a marked modification of the longitudinal profile of the Río Toro, due to the systematic aggradation of the reach situated close to the confluence between the two streams. A direct consequence is affecting of the bridge of “Ruta Nacional 51”, situated in the immediate vicinities of the confluence, where often in the period of summer rains (when the water discharge increases) the overflowing of Río Toro occurs, with floods that produce the interruption of this important road. In fact, the aggradation of the river bed due to the accumulation of detrital material (that usually cannot be eroded by low water discharge), when the discharge in the Río Toro is increasing, during the summer period, produces easily the over flow of the stream, flooding the lower Ruta Nacional 51. The available data show that the defense built dur ing the ‘80s to protect the road (two meters in height over the river bed), now are completely buried due to the floods produced by the debris flows from the Quebrada del Candado. A solution to the problems of the Río Toro in this reach, related to the processes of debris flows, could consist both in the construction of works intercepting the solid transport, and above all, defense works from the erosion of the slopes, to prevent the source of mobilization of the detrital material within the catchment of the Río Candado.

Downloads

Published

2011-11-30

How to Cite

Cencetti, C., & Rivelli, F. (2011). Landslides dams induced by debris flows in quebrada del toro (province of Salta, Argentina). Italian Journal of Engineering Geology and Environment, 645–650. https://doi.org/10.4408/IJEGE.2011-03.B-070