Rock glaciers as a water resource in a changing climate in the semiarid Chilean Andes

Rock glaciers likely play an important hydrological role in the semiarid Andes (SA; 27 degrees-35 degrees S). They supplement streamflow when water is needed most, especially during dry years in the late summer months. Despite their assumed importance, there are no publications that quantify their hydrological contribution to streamflow in the SA of Chile, based on measurements of rock glacier ice loss or discharge. In this study, we assess the available information on the hydrological importance of rock glaciers in the SA and provide suggestions on how future research can address knowledge gaps. We conclude that there is insufficient data available to quantify the hydrological contribution of rock glaciers in the SA. Measurements of glacier discharge are limited to unpublished data sets from which only very limited conclusions can be drawn. There are no ice volume change measurements or proxies available for individual rock glaciers. Approximations of rock glacier ice volume, calculated from areal extent, thickness, and percentage of ice content are available, and these data provide an initial baseline for calculating ice volume change in the future. While these baseline data are very valuable, they represent rough estimates due to a scarcity of studies, especially on glacier thickness and percentage of ice content. With increased temperatures and a decrease in precipitation expected in the future, rock glaciers could become an increasingly critical water resource in this region, especially in the Elqui and Juncal catchments. Improved estimates of rock glacier discharge, water content, processes, and hydrology are required to model their future evolution and evaluate their contribution to water resources.