Application of isotope techniques to enhance the conceptual hydrogeological model and to assess groundwater sustainability in the Pampean plain in Córdoba, Argentina

ABSTRACT

The objective of this work is to enhance the conceptual hydrogeological model in the Río Cuarto River basin by using isotope and hydrochemical techniques. The precipitation pattern, as reflected in the average values of δ²H and δ¹⁸O in stations located in the plains and in the mountains, showed an isotope depletion from the East to the West, attributed to continental and altitude effects. Groundwater quality is mainly the result of two controlling factors: lithology and flow distances from recharge. The aquifers show fresh calcium/sodium bicarbonate water in the upper and medium basin (coarse fluvial sediments) which evolve to sodium sulphate and chloride waters in the low basin (mainly loess and fine alluvial sediments). The confined aquifer systems in the lower basin (C and D systems) averaged more negative stable isotope values, indicating that groundwater recharged during colder climatic conditions (Pleistocene period). Groundwater dating with ¹⁴C confirmed that groundwater ages range from modern to 45,000 years BP showing that as the water flows towards deeper layers and farther from the mountainous recharge area, groundwater age increases. The confined aquifers can potentially be exploited in order to partly cover different water needs but they should be managed in a sustainable way.

KEYWORDS:

• Age dating
• carbon-14
• deuterium excess
• groundwater
• hydrogen-2
• hydrogeochemistry
• isotope hydrology
• oxygen-18
• Pampean plain

Acknowledgments

We appreciate the suggestions of two anonymous reviewers and the editor to improve the article.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The work was supported by research projects: a) Coordinated Research Project (CRP): “Isotope Techniques for the Evaluation of Water Sources for Domestic Supply in Urban Areas (F33024)”-IAEA (International Atomic Energy Agency-Vienna, Austria): “Use of Conventional and Isotope Techniques for the Evaluation of Water Resources for Domestic Supply in Urban Areas Threatened by Surrounding Agricultural Activities in the Pampean Plain”. b) PICT (Scientific and Technological Research Projects) 474-FONCYT (Fund for Scientific and Technological Research-Argentina) and c) PPI-SECYT UNRC (Research Programs and Projects of National University of Río Cuarto, Córdoba, Argentina).