Integrated hydrostratigraphic and geophysical characterization of the El Carrizal aquifer (Baja California Sur, Mexico): Insights for groundwater management in an arid basin

This study presents an integrated hydrostratigraphic and geophysical characterization of the El Carrizal aquifer in southern Baja California Sur, Mexico, one of the main groundwater sources for agricultural and domestic use in this arid region. The analysis combines piezometric information, well data, and surface geophysical surveys, including Vertical Electrical Soundings (VES) and the Frequency–Selection Method (FSM), to investigate the internal architecture of the basin fill and its hydrostratigraphic heterogeneity.Results indicate a heterogeneous sedimentary system composed of coarse alluvial deposits along the basin margins and thick fine-grained alluvial to lacustrine sediments toward the central valley. Resistivity patterns derived from VES and FSM data allow identification of laterally and vertically contrasting hydrostratigraphic domains, characterized by significant variations in permeability and groundwater storage potential. These domains influence the spatial distribution of recharge areas, preferential flow paths, and zones of reduced transmissivity within the aquifer.The integrated interpretation provides new insights into sediment thickness and the spatial variability of basin-fill sediments improving the conceptual understanding of groundwater flow in the basin. The results highlight the value of combining low-cost geophysical methods with hydrogeological data to support groundwater management in data-scarce arid regions. Overall, the study provides a hydrostratigraphic framework for the surveyed sector of the El Carrizal aquifer, with broader relevance to groundwater assessment in arid alluvial systems.