Sources of surface water for the soncor lagoon ecosystem, Salar de Atacama basin, northern Chile.

Abstract

The Salar de Atacama is located in the most arid desert of the world. Despite its extreme conditions, it has many ecosystem of high ecological value. The Soncor ecosystem, a sequence of lagoons, is the most important environment of the region as acts as the centre for the breeding of the Andean Flamingo. This salt flat also contains significant mining deposits and is an important water source for the region. Freshwater and brine –enriched in lithium and potassium– are being pumped from the aquifers nearby the Soncor ecosystem, which so far has not been greatly affected by these groundwater extractions. However, there is a potential risk that future anthropogenic effects can disturb this fragile environment. The objective of this study is to determine the origin of the water sources of the Soncor ecosystem to adequately manage its water resources. Three hypotheses previously proposed by the technical literature were investigated in order to propose proactive actions to protect this fragile ecosystem. The study utilized classic hydrogeological techniques such as the construction of stratigraphic profiles, piezometric maps, and stream gauging, combined with isotopic techniques that are less common, such as the 87Sr/86Sr ratio. The results confirmed the hypothesis that the origins of the water sources are associated to groundwater inputs coming from the east side of the salt flat, in the north of the basin.