Hydrogeology and groundwater development in a salar basin in the Andes Mountains of northern Chile

Abstract

A closed salar basin, 4,100 to more than 5,350 meters above mean sea level, is a potential source of fresh groundwater for proposed mining operations in the arid Andes Mountains of northern Chile. The prolific basin aquifer, comprised of alluvial deposits underlain by fractured ignimbrite, occurs over an area of 23 square kilometers. Transmissivity ranges from 20 to 7,100 square meters per day. Volume of potentially recoverable groundwater is equal to a constant yield of 200 liters per second for 30 years. Groundwater discharge occurs via evaporation at the salar, and is in approximate equilibrium with groundwater recharge. Projected long-term combined pumping rate from two proposed production wells is 164 liters per second. This pumping rate is in the same magnitude as evaporation at the salar. Proposed pumping would diminish surface water supplies in the basin, and would result in a new dynamic equilibrium for the groundwater system.