Abstract

Rapidly retreating glaciers in the arid tropics are an invaluable resource for communities that depend on meltwater to support drinking water, agriculture, hydropower production, and mining. There is limited understanding of how glacier loss will impact regional water resources, groundwater flow paths, and water quality, especially during the dry season. The Nevado Coropuna volcano in Southern Peru has one of the largest remaining ice caps in the tropics, but has experienced rapid ice loss in the past few decades and is projected to disappear in the next century due to climate change. Located in the northern Atacama Desert, the arid Coropuna volcano rises 6,400 m elevation in 115 km distance from the Pacific Ocean. To investigate the role of glaciers on water resources and water quality downstream the Coropuna ice cap, we sampled streams, cold springs, thermal springs, and glacial meltwater around the volcano during the dry season of 2019, 2022, and 2023. We used stable water isotopes to determine the relative amount of water sourced from glacier melt versus lower elevation rain, and trace and major element chemistry to identify geochemical processes leading to water quality impairments. The results of a stable isotope mixing model showed that springs and streams located on the north side of Coropuna were more glacially dominated (60-100%) compared to water on the south side (< 50%). Using a principal component analysis, we identified three potential endmembers contributing to water chemistry, including a dilute endmember and two possible weathering pathways corresponding to different bedrock types. Trace elements Al, As, B, Be, Cs, Fe, La, Li, Mg, Mn, and Na exceeded drinking water standards in many of our sampling sites, especially those located on the south side of Coropuna. As the Coropuna ice cap continues to shrink, water resources will likely diminish on the north side of the volcano, while water quality will continue to present a a public health concern on the south side. Our study has implications for understanding water resources and water quality in glaciated watersheds that are experiencing rapid ice loss due to climate change, particularly in the arid Andes of Peru.

Degree

MS

College and Department

Geological Sciences; Computational, Mathematical, and Physical Sciences

Rights

https://lib.byu.edu/about/copyright/

Date Submitted

2024-12-19

Document Type

Thesis

Keywords

tropical glaciers, climate change, water chemistry, thermal springs, Coropuna ice cap, Peru

Language

english

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