Abstract

Laguna Santa Rosa (LSR) is a hypersaline lake located at the southern tip of the Maricunga salt flat in the Atacama Region of Chile, whose water volume directly affects flora and fauna of the sector since this groundwater-dependent wetland is part of the ecosystem for the species inhabiting this highland sector of the Andes. To analyze the historical and current status of LSR and to assess its variability over time, the variation in the extent of the lake was established through the application of Landsat-5 TM satellite image collection both for the hydrological year 2016-2017 and for a period of 1993-2014 to delimit the transgression and regression of this wetland and project the future trends. A continuous decrease in the water level of LSR was observed between 1993 and 2014, showing the lake's shrinking. However, this contraction trend was punctuated by extreme rainfall and consequent flood with accumulated precipitation exceeding 40 mm in a single day and hourly mean rainfall rates higher than 10 mm/hour at several locations in the hyperarid Atacama Desert on March 25, 2015. This raised the lake's water level, and thus the areal extent of the lake water observed in the satellite images of the period 2016-2017 following the extreme weather events of 2015. The interplay of these extreme weather events and groundwater extraction for mining activities in the area makes assessing the latter’s effect rather complex and limited to the intervals between successive extreme weather events.