Spatially heterogeneous discharge of glacial meltwater to drainages surrounding the ablating Coropuna ice cap, Peruvian Andes

ABSTRACT

As tropical glaciers recede in response to global warming, glaciated watershed resilience is threatened by the loss of these important water reservoirs. In the Cordillera Occidental, Peru, we investigate the importance of glacial meltwater to mountain groundwater recharge and subsequent discharge to streams surrounding the rapidly retreating Coropuna ice cap. Using stable isotopes, solute concentrations, and radiocarbon activity, our results suggest that in remote ungauged systems, glacial input can be determined via geochemical analysis and a simple mixing model approach. We find that the proportion of glacial meltwater contribution to groundwater and surface waters is spatially heterogeneous. Differences between drainages are attributed to the degree of melting of headwater glaciers and the routing of waters through volcanic strata. These results provide evidence that glacial meltwater recharge is highly variable even within the same mountain block. Furthermore, the effects on streamflow will be disproportionate as the watersheds approach an ice-free state.

KEYWORDS:

• glacial meltwater
• stable isotopes
• radiocarbon
• mountain-block recharge
• Andes
• climate change

Editor A. Fiori; Associate Editor G. Jeelani

Editor A. Fiori; Associate Editor G. Jeelani

Acknowledgements

Special thanks to Wilbur and Melissa Sivincha for sample collections. We would like to thank Dr. Ghulam Jeeelani and anonymous reviewers whose comments helped to significantly improve the manuscript.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Supplementary material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/02626667.2024.2352522.

Additional information

Funding

This work was supported by the Universidad Nacional de San Agustín de Arequipa [NEXUS Consortium].