Hydrogeology and sustainable future groundwater abstraction from the Agua Verde aquifer in the Atacama Desert, northern Chile

Urrutia, Javier; Jódar, Jorge; Medina, Agustín; Herrera, Christian; Chong, Guillermo; Urqueta, Harry; Luque, José A.

Hydrogeology and sustainable future groundwater abstraction from the Agua Verde aquifer in the Atacama Desert, northern Chile | Hydrogéologie et future exploitation durable d’eau souterraine au sein de l’aquifère d’Agua Verde dans le désert d’Atacama, Nord du Chili Hidrogeología y futura explotación sostenible de agua subterránea del acuífero Agua Verde en el Desierto de Atacama, norte de Chile 智利北部Atacama沙漠Agua Verde含水层水文地质状况及未来可持续的开采量 Hidrogeologia e abstrações futuras de águas subterrâneas a partir do aquífero Agua Verde no Deserto do Atacama, norte do Chile

2018

The hyper-arid conditions prevailing in Agua Verde aquifer in northern Chile make this system the most important water source for nearby towns and mining industries. Due to the growing demand for water in this region, recharge is investigated along with the impact of intense pumping activity in this aquifer. A conceptual model of the hydrogeological system is developed and implemented into a two-dimensional groundwater-flow numerical model. To assess the impact of climate change and groundwater extraction, several scenarios are simulated considering variations in both aquifer recharge and withdrawals. The estimated average groundwater lateral recharge from Precordillera (pre-mountain range) is about 4,482 m³/day. The scenarios that consider an increase of water withdrawal show a non-sustainable groundwater consumption leading to an over-exploitation of the resource, because the outflows surpasses inflows, causing storage depletion. The greater the depletion, the larger the impact of recharge reduction caused by the considered future climate change. This result indicates that the combined effects of such factors may have a severe impact on groundwater availability as found in other groundwater-dependent regions located in arid environments. Furthermore, the scenarios that consider a reduction of the extraction flow rate show that it may be possible to partially alleviate the damage already caused to the aquifer by the continuous extractions since 1974, and it can partially counteract climate change impacts on future groundwater availability caused by a decrease in precipitation (and so in recharge), if the desalination plant in Taltal increases its capacity.

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