Resumo

BOUJON, Pamela  e  SANCI, Romina. Evaluación de la vulnerabilidad del acuífero libre en la cuenca del arroyo El cura, Gualeguaychú, Entre ríos. Rev. Asoc. Geol. Argent. [online]. 2014, vol.71, n.2, pp.275-291. ISSN 0004-4822.

The work analyses the basin of the Stream El Cura, south of the city of Gualeguaychú, Entre Ríos, where the town’s landfill is located. With the objective of evaluating the vulnerability to pollution of the free aquifer, the geology and hydrogeology of the area were studied. Two loessic levels of the middle and superior pleistocene age, (Hernandarias and Tezanos Pintos Formations) containing the phreatic aquifer were identified. The effluent character of the stream, with a SW to NE main direction of the underground flow and with regional hydraulic gradients on the order of 0,0016 could be determined from the piezometric analysis. The salinity of the underground water shows an increase in accordance to that direction. A direct relationship was found between the geomorphological units defined for the basin (PL, PA and TPRG) and the chemistry of the groundwater that evolves from bicarbonate calcium in PL to bicarbonate sodium in PA and TPRG. The relationship between the piezometric levels and groundwater hydrochemistry allowed inferring recharge and discharging zones. The three methodologies applied to establish the areas vulnerable to pollution and the degree of vulnerability of the basin were: EKv, GOD and GODS. The most effective method was the GODS, obtaining three degrees of vulnerability basically associated with geomorphological units (high for TPRG; moderate for PA and low for PL), and to the lithologies that compose them. Likewise it was observed that the most vulnerable areas are associated with the lowest piezometric levels.

Palavras-chave : Environmental hydrogeology; Hydrochemistry; Landfill.

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