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Role of low-Glacierized Basins and Groundwater in semiarid Andes Periglacial Headwaters
  • +11
  • Rémi Valois,
  • Gonzalo Navarro,
  • Shelley MacDonell,
  • Solène Buvat,
  • Giulia de Pasquale,
  • Vincent Marc,
  • Marina Gillon,
  • Esteban Saez Robert,
  • Ayon Garcia,
  • Christopher Ulloa,
  • Julien DUPONT,
  • Milanka BABIC,
  • Eric Sproles,
  • Etienne Bresciani
Rémi Valois
Avignon Universite

Corresponding Author:remi.valois@univ-avignon.fr

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Gonzalo Navarro
Universidad de La Serena
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Shelley MacDonell
Centro de Estudios Avanzados en Zonas Aridas
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Solène Buvat
Universite Clermont Auvergne Polytech Clermont
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Giulia de Pasquale
Centro de Estudios Avanzados en Zonas Aridas
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Vincent Marc
Avignon Universite
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Marina Gillon
Avignon Universite
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Esteban Saez Robert
Pontificia Universidad Catolica de Chile Centro de Bioetica
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Ayon Garcia
Universidad de Atacama
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Christopher Ulloa
Universidad de Atacama
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Julien DUPONT
Avignon Universite
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Milanka BABIC
Avignon Universite
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Eric Sproles
Montana State University Department of Earth Sciences
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Etienne Bresciani
Universidad de O'Higgins
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Abstract

A better understanding of headwater hydrogeology in the semi-arid Andes is critical because high-elevation basins are considered water towers for the main valleys, where water demand is the highest. Geophysical surveys and a pumping test were carried out to obtain information on aquifer structures and properties. Radioactive and stable isotopes were used to characterize the hydrological functioning of the headwater basins. Low electromagnetic velocities and resistivities reveal the presence of liquid water beneath a rock glacier, which could be the upper limit of a proglacial aquifer. The downstream valley aquifer appears fairly transmissive (3.2 10 -3 m 2s -1) and dominated by old waters (several decades) that are a mix of high-glacierized and low-glacierized basins. Additionally, stable isotopes point out a different signature for high-glacierized and low-glacierized basins, which could result from isotope fractionation. These results indicate that water isotopes could be used to discriminate waters originating from high-glacierized and low-glacierized basins. The study identifies the presence of old waters in a priori low-glacierized basins, which indicates long term storage. This finding is important for understanding late season baseflow and streamflow evolution in the context of climate change. As the contribution of such basins to total streamflow is significant, studies that aim to predict streamflow should not only focus on basins containing large glaciers.
05 Jun 2024Submitted to Hydrological Processes
06 Jun 2024Submission Checks Completed
06 Jun 2024Assigned to Editor
10 Jun 2024Reviewer(s) Assigned