Joint use of piezometric surfaces and chemical and isotopic tracers to identify recharge areas in arid environments: Agrelo fan area, Mendoza province, Argentina

Abstract

Although there are numerous hydrogeological papers on the Abanico de Agrelo area due to its importance from the point of view of recharge to the Mendoza Northern Basin, many uncertainties still remain to be solved. The aim of this study is to obtain new data to update and improve the conceptual model of the aquifer. For this purpose, we have carried out a desktop review of the previous data and the aquifer dynamics have been redefined. Based on this information, a hydrochemical and isotopic sampling was carried out in order to confirm the hydrogeological dynamics. Our results indicate that the main flow of the aquifer is NW-SE and that although the river is the main source of recharge, there could be other input areas. The hydrochemical data confirm this dynamic, showing a gradual enrichment of salts in the flow direction. The hydrochemical underground pattern is similar to that of the river, but it shows lower conductivity values in the nearby areas, in Cadicating a probable mixture of water from another recharge source. The resulting conceptual model considers that the hydrogeological system of the Abanico de Agrelo extends to both banks of the Mendoza River and that the river is not an edge of the aquifer itself as it works as an indirect recharge area. The existence of additional recharge sources is also proposed in this paper.