Storage-Release Mechanism in Lunette Systems Enhance Shallow Lake Resilience Under Multi-Year Drought

Shallow lake persistence in humid continental plains under increasing climate variability requires adequate subsurface storage capacity, yet how inherited landforms from past arid periods regulate modern hydrological resilience remains poorly understood. This study demonstrates that lunette deposits—crescent-shaped aeolian landforms—function as active natural infrastructure controlling contemporary shallow lake stability during multi-year droughts through a quantifiable storage-release mechanism. During the 2021-2023 regional drought, Las Barrancas (Argentine Pampas), featuring South America’s most pronounced lunette (18 m high), maintained minimum 60% water surface area while three morphologically similar regional lakes lacking pronounced lunettes experienced complete desiccation, directly validating differential resilience controlled by inherited geomorphology. Through integrated paleogeomorphological reconstruction, geophysical prospecting, continuous hydrodynamic monitoring, hydrochemical characterization, and comparative remote sensing validation across four regional systems, we revealed the regulatory mechanism: lunettes progressively store water during humid periods through enhanced subsurface storage capacity exceeding regional aquifer values twofold, which is subsequently released during droughts through sustained groundwater discharge representing ~70% of total groundwater inputs—the critical difference between system persistence and failure. Hydrochemical characterization confirms persistent geomorphological control: rapid salinization within lunette sediments through dissolution of preserved evaporitic minerals versus gradual evolution along regional flow paths, demonstrating how paleoclimatic heritage actively controls contemporary water chemistry. This research establishes that landscape inheritance from past arid periods constitutes measurable natural infrastructure providing hydrological resilience, with direct implications for nature-based climate adaptation strategies in vulnerable continental plains globally where preservation of inherited geomorphological features may prove critical for ecosystem persistence under projected drought intensification.