A multi-parameter study of groundwater–seawater interactions along Partido de La Costa, Buenos Aires Province, Argentina

CARRETERO, SILVINA; RAPAGLIA, JOHN; PERDOMO, SANTIAGO; ALBINO MARTÍNEZ, CARLOS; RODRIGUES CAPÍTULO, LEANDRO; GÓMEZ, LUCÍA; KRUSE, EDUARDO

Environmental Earth Sciences

Springer

Año: 2019 vol. 78

1866-6280

Submarinegroundwater discharge (SGD) is a complex hydrological process which occurs atthe continent?ocean interface and plays an important role in coastal dynamics.The main objective of this study was to detect groundwater discharge from thesandy freshwater aquifer towards the Atlantic Ocean along the western coast ofBuenos Aires Province (Argentina) using multiple methods. 222Rn as atracer, electrical resistivity tomography (ERT) and hydrogeological informationwere applied to detect and quantify SGD. 222Rn activity was measuredin wells, at the beach (tidal pools and surf zone) and along a transect ~200mfrom the coastline coincident with geoelectrical measurements. Groundwaterdepth was measured in wells and from these data groundwater contour maps weremade. 222Rn activity in wells varies from 16 and 173 dpm/L, at thebeach the values are between 28 and 48 dpm/L and along the coastline theyoscillate between 1.3 and 20.5 dpm/L. The ERT shows a high resistivity layerclose to 3-4 m depth from the sea floor indicating the presence of freshwater.Groundwater contour maps show discharge toward the continental plain to thewest and toward the sea to the east. There is no precedent related to theapplication of these methodologies in the study area which results of interestfor the knowledge of the coastal hydrodynamics.