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Evaluation of aquifer recharge into Salto Chico, Hernandarias and Ubajay formations. Palmar Creek, Entre Ríos, Argentina

2021; Spanish National Research Council; Volume: 132; Issue: 3 Linguagem: Inglês

10.21701/bolgeomin.132.3.002

2253-6167

Adrián Silva Busso, Luis Moreno Merino, Mario Chury,

Groundwater and Isotope Geochemistry

The study of recharge mechanisms and volumes in aquifers is one of the most important issues for achieving sustainable exploitation of the groundwater resource. This factor has an impact on agricultural productivity as irrigation increases the yields of many crops and agriculture is the main economic activity in Argentina. However, recharge studies are not common in the country and this is why this paper is a new contribution. We have carried out a detailed study of the soil and hydrogeology in a hydrological basin. This basin is in an agricultural area typical of the Pampean region. Detailed records of precipitation, soil moisture and hydraulic head have been collected from stations designed for this purpose. We have also analyzed the influence and magnitude of vertical recharge from a water balance in the unsaturated zone. The calculation of the net recharge has also been included in the saturated zone. We have shown that the geological conditions of the basin influence the aquifer recharge. In outcrop zone of F. Ubajay the infiltration of surpluses allows a vertical transit equivalent to 6.61% with net recharge values of 1.41% of precipitation. In the outcrop zone of F. Hernandarias the conditions do not favour the infiltration of water surpluses and only allow a transit equivalent to 0.89% with a net recharge of 0.04% of precipitation. This scenario suggests that vertical recharge is not a dominant or quantitatively important process, which is atypical in Argentina’s Pampean region. These values are far from those previously established which varied between 7% and 15% of the average annual rainfall. The implications for water management in the region are significant and make it necessary to rethink the conceptual model of the aquifers in the area