Rapid recharge of fresh water to the halite‐hosted brine aquifer of Salar de Atacama, Chile

Abstract

We document, analyse, and interpret direct and rapid infiltration of precipitation to the southern margin of the Salar de Atacama halite‐hosted brine aquifer during two intense precipitation events in 2012–2013. We present physical, geochemical, and stable and radioactive isotope data to detail this influx of water. The two events differ distinctly in the mechanisms of recharge. The 2012 event did not produce direct precipitation onto the salar surface, while the 2013 event did. Both events are recorded by abrupt changes in head in observation wells along the halite aquifer margin. Spatially distributed water levels rose by over 30 cm during the larger 2013 event consistent with remotely sensed observations of surface water extent. The lithium concentration and stable isotopic composition of water indicate dilution of brine and dissolution of salt with fresh water. Tritium measurements of precipitation, surface water, and groundwater all indicate modern influx of water to the halite aquifer along the southern margin. We extend these observations by examining the response of the halite aquifer as a whole to precipitation events during the period of 2000–2010. This study suggests that local recharge to the aquifer during sporadic precipitation onto the halite nucleus is an important component of the modern water budget in this hyper‐arid environment. The rapid dissolution and salinization along the southern margin of the salar halite nucleus are aided by such precipitation events contributing a modern fresh water component to the water budget of the economically valuable lithium‐rich brine. Copyright © 2016 John Wiley & Sons, Ltd.

Imbalance in the modern hydrologic budget of topographic catchments along the western slope of the Andes (21–25 S)

“…The SdA basin, in the core of Atacama Desert, is characterized by a hyperarid to arid climate [Hartley and Chong, 2002]. Significant inter-annual precipitation variability [Garreaud et al, 2003] includes infrequent high-intensity rainfall events that produce pulsed groundwater recharge [Houston, 2006b;Boutt et al, 2016]. Because the basin has been closed since at least the late Miocene [Jordan et al, 2002a], surface water discharge occurs only through evapotranspiration.…”

“…orogenic groundwater) and systematic errors in ET and/or GW RCH estimates could also explain portions of the imbalance. Infrequent, high-intensity precipitation events are known to rapidly recharge the groundwater system in areas where the water table is near the surface [Boutt et al, 2016]. For the brine budget of SdA, such events are important to balance discharge from pumping and the low ET rates (<0.1 mm/year) in the halite Manuscript submitted for Review in Hydrological Processes -November 13, 2018 13 aquifer.…”

Cropland Soil Salinization and Associated Hydrology: Trends, Processes and Examples

“…This process is the cause of the formation of many of the salinized soils found in dry areas around the world [43,[76][77][78], with an estimated total area of about 350 × 10 4 km 2 [9]. An example of soil salinization in an agricultural region, due to the presence of shallow and salty groundwater can be seen in the Gerar wash basin in the Northern Negev desert, Israel (Figure 3).…”

Preface for the South American Hydrology Virtual Special Issue

“…Five papers investigate groundwater–surface water interactions across a variety of South American landscapes. Boutt, Hynek, Munk, and Corenthal () investigated recharge processes to the halite‐hosted brine aquifer of the economically important lithium brine of the Salar de Atacama in Nothern Chile. Rapid infiltration from modern precipitation in the form of infrequent precipitation events bypass the long‐flow paths of regional groundwater from the Altiplano recharge regions.…”

“…Two papers studied vegetation responses to agriculture expansion (Giménez, Mercau, Nosetto, Páez, & Jobbágy, 2016) and rainfall variability (Souza et al, 2016), and a third characterized runoff generation processes in a high-elevation tropical ecosystem (Mosquera et al, 2016) Five papers investigate groundwater-surface water interactions across a variety of South American landscapes. Boutt, Hynek, Munk, and Corenthal (2016) investigated recharge processes to the halitehosted brine aquifer of the economically important lithium brine of the Salar de Atacama in Nothern Chile. Rapid infiltration from modern precipitation in the form of infrequent precipitation events bypass the long-flow paths of regional groundwater from the Altiplano recharge regions.…”