GroMoPo Metadata for Pampa del Tamarugal 2016 regional model

Aquifers within the Pampa del Tamarugal Basin (Atacama Desert, northern Chile) are the sole source of water for the coastal city of Iquique and the economically important mining industry. Despite this, the regional groundwater system remains poorly understood. Although it is widely accepted that aquifer recharge originates as precipitation in the Altiplano and Andean Cordillera to the east, there remains debate on whether recharge is driven primarily by near-surface groundwater flow in response to periodic flood events or by basal groundwater flux through deep-seated basin fractures. In addressing this debate, the present study quantifies spatial and temporal variability in regional-scale groundwater flow paths at 20.5A degrees S latitude by combining a two-dimensional model of groundwater and heat flow with field observations and delta O-18 isotope values in surface water and groundwater. Results suggest that both previously proposed aquifer recharge mechanisms are likely influencing aquifers within the Pampa del Tamarugal Basin; however, each mechanism is operating on different spatial and temporal scales. Storm-driven flood events in the Altiplano readily transmit groundwater to the eastern Pampa del Tamarugal Basin through near-surface groundwater flow on short time scales, e.g., 10(0)-10(1) years, but these effects are likely isolated to aquifers in the eastern third of the basin. In addition, this study illustrates a physical mechanism for groundwater originating in the eastern highlands to recharge aquifers and salars in the western Pampa del Tamarugal Basin over timescales of 10(4)-10(5) years.

位于智利北部阿塔卡马沙漠的帕马普塔马尔瓜尔山谷盆地内的含水层是伊基克沿海城市及具有重要经济价值的采矿业的唯一水源。尽管如此，该地区的地下水系统仍理解不足。尽管普遍认为含水层补给源于东部的阿尔蒂普拉诺和安第斯山脉的降水，但对于补给主要是由周期性洪水事件引起的近地表地下水流动还是由深部盆地裂缝中的基础地下水流动驱动，仍存在争议。为了解决这一争议，本研究通过结合地下水与热流二维模型、现场观测以及地表水和地下水中δO-18同位素值，在20.5°S纬度上量化了区域尺度地下水流动路径的空间和时间变化。结果表明，先前提出的两种含水层补给机制均可能影响帕马普塔马尔瓜尔山谷盆地内的含水层；然而，每种机制都在不同的空间和时间尺度上运作。在阿尔蒂普拉诺的暴雨驱动洪水事件中，地下水可以迅速通过短时间尺度（例如，10(0)-10(1)年）的近地表地下水流动传输到东部帕马普塔马尔瓜尔山谷盆地，但这些影响可能仅限于盆地东部的三分之一。此外，本研究还阐述了地下水起源于东部高地，并在10(4)-10(5)年的时间尺度上为西部帕马普塔马尔瓜尔山谷盆地的含水层和盐沼进行补给的一种物理机制。