Geomorphological constraints in groundwater chemistry at a regional recharge area in the Pampean plain, Córdoba, Argentina

YACIUK, PABLO A.; BLARASIN, MÓNICA T.; CABRERA, ADRIANA E.; ECHEGOYEN, CECILIA V.

HYDROGEOLOGY JOURNAL

SPRINGER

Año: 2023

1431-2174

The El Cano stream basin is located in the Pampean Plain of Argentina, which is one of the most productive agricultural regions in the world. Within this plain, groundwater is the main water source for agriculture, cattle breeding, and industrial and domestic activities. Nonetheless, scarce information is available regarding groundwater quality and distribution, as well as the importance of this basin as a regional groundwater recharge zone. Through hydrochemical, groundwater-flow, and multivariate statistical analyses, this study relates groundwater physico-chemical characteristics with the geological features of the territory. Results show that waters are alkaline, dominantly of the bicarbonate type, and fresh to brackish, with electrical conductivity ranging between 461 and 2,945 μS cm−1. Four main geomorphological units are recognized in the basin: the Mountain Range (MR), the Piedmont Belt (PB), the Alluvial Plains (AP), and the Fluvio-Eolian Plains (FEP). Groundwater from the MR and AP show better quality than the PB and FEP. Furthermore, the FEP display the basin’s highest concentrations of fluoride and arsenic. The influence of (1) local precipitation, (2) infiltration of surficial water, and (3) the lithology, mineralogy, and grain size of the materials constituting the aquifer (which are highly variable among the different geomorphological units), are interpreted to be the main features determining the physico chemical characteristics of the groundwater.