Evaluating the Sustainability and Adaptability of the Maipo-Mapocho Aquifer under Climate Change Projections

Ensuring water security under increasing population pressure, agricultural expansion, and climate change remains a major global challenge. Groundwater plays a critical role, supplying more than half of global drinking water and supporting irrigation, yet it is increasingly threatened by overexploitation and declining recharge. In central Chile, the Maipo–Mapocho aquifer is a key resource, sustaining urban and agricultural demands and supporting nearly 40% of the national population during the ongoing megadrought that began in 2010. This study evaluates aquifer sustainability under current and future conditions using a MODFLOW-based hydrogeological model for the 2021–2050 period, considering the SSP5-8.5 scenario and multiple global climate models. Results indicate recharge reduction of 10% to 47% and groundwater level declines exceeding 50 m in many areas and 100 m in the most impacted zones. Three adaptation levels were assessed, incorporating demand reduction, adaptive extraction, and new water sources. Results show strong spatial variability, with critical depletion in Northern Zone and storage losses of 36%–60% in central areas. Medium and high adaptation significantly mitigate impacts, highlighting the need for integrated, climate-resilient strategies to ensure long-term water security.