Glacier contributions to river discharge during the current Chilean megadrought

McCarthy, Michael ORCID: https://orcid.org/0000-0001-8099-0531; Meier, Fabienne; Fatichi, Simone; Stocker, Benjamin D.; Shaw, Thomas E.; Miles, Evan; Dussaillant, Inés; Pellicciotti, Francesca. 2022 Glacier contributions to river discharge during the current Chilean megadrought. Earth's Future, 10 (10), e2022EF002852. 15, pp. 10.1029/2022EF002852

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Abstract/Summary

The current Chilean megadrought has led to acute water shortages in central Chile since 2010. Glaciers have provided vital fresh water to the region’s rivers, but the quantity, timing and sustainability of that provision remain unclear. Here we combine in-situ, remote sensing and climate reanalysis data to show that from 2010 to 2018 during the megadrought, unsustainable imbalance ablation of glaciers (ablation not balanced by new snowfall) strongly buffered the late-summer discharge of the Maipo River, a primary source of water to Santiago. If there had been no glaciers, water availability would have been reduced from December through May, with a 31 ± 19% decrease during March. Our results indicate that while the annual contributions of imbalance ablation to river discharge during the megadrought have been small compared to those from precipitation and sustainable balance ablation, they have nevertheless been a substantial input to a hydrological system that was already experiencing high water stress. The water-equivalent volume of imbalance ablation generated in the Maipo Basin between 2010 and 2018 was 740 × 106 m3 (19 ± 12 mm yr-1), approximately 3.4 times the capacity of the basin’s El Yeso Reservoir. This is equivalent to 14% of Santiago’s potable water use in that time, while total glacier ablation was equivalent to 59%. We show that glacier retreat will exacerbate river discharge deficits and further jeopardise water availability in central Chile if precipitation deficits endure, and conjecture that these effects will be amplified by climatic warming.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	10.1029/2022EF002852
ISSN:	2328-4277
Additional Keywords:	Glaciers, Megadrought, Chile, Streamflow, Sustainability, Water supply
Date made live:	14 Sep 2022 08:30 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/533212

Item Type:

Publication - Article

Digital Object Identifier (DOI):

10.1029/2022EF002852

ISSN:

2328-4277

Additional Keywords:

Glaciers, Megadrought, Chile, Streamflow, Sustainability, Water supply

Date made live:

14 Sep 2022 08:30 +0 (UTC)

URI:

https://nora.nerc.ac.uk/id/eprint/533212