MORPHOMETRIC, GEOMORPHOLOGIC AND FLOOD HAZARD ANALYSIS OF AN ARID MOUNTAIN RIVER BASIN, CENTRAL PRE-ANDES OF ARGENTINA. SOUTHWESTERN SOUTH AMERICA

ROTHIS, LUIS MARTÍN; LARA FERRERO, GABRIELA; L. PERUCCA

GEOGRAFIA FISICA E DINAMICA QUATERNARIA

COMITATO GLACIOLOGICO ITALIANO

Lugar: Torino - Italia; Año: 2018 vol. 41 p. 83 - 97

1724-4757

A geomorphologic and morphometric analysis was performed in orderto determine the characteristics of the de La Ciénaga river basin, anarid mountain river basin located in the southwest of San Juan Province(31°45´S, 68°50´W), Central Pre-Andes, Argentina. The drainagenetworks were derived from shuttle radar topographic mission (SRTM)data, satellite imageries (Landsat TM and Spot image) and field works.The paper also addresses a preliminary evaluation of the flood hazard responsiblefor severe damage to farming and infrastructure in the downstreamregion. The study basin area covers almost 700 km2, comprisingfive sub-basins, ranging from 111.96 to 159.30 km2. The asymmetricalmorphology of the basin, neotectonic features and the diversity of alluvialdeposits found along the de La Ciénaga river basin show that it is inan active tectonic environment with strong lithological and structuralcontrols and a marked tilting. One common feature to all analyzed sub--basins is their elongated shape, which allows a rapid concentration ofwater that intensifies the power of the flash floods. The drainage networkin the different sub-basins has, in general, two predominant patterns; oneis parallel to sub-parallel to the headers and foothill areas; and the other,in the piedmont zone, is divergent. Zonda valley, located downstream ofthe basin, is affected by flash floods coming from the mountainous area.