The aquifer system of the Salado-Juramento Fluvial Megafan distal plain, South America: an integrated 1 approach of geological, hydrogeological and numerical models

THALMEIER, MARIA BELEN ; RODRÍGUEZ, LETICIA; HEREDIA, JAVIER ; KRÖHLING, DANIELA M.; BRUNETTO, ERNESTO

HYDROGEOLOGY JOURNAL

SPRINGER

Lugar: Berlin; Año: 2024

1431-2174

The hydrogeological system of a large plain in South America, the Bajos Submeridionales (BBSS), still needs to 11 be better understood. BBSS is located in the distal part of one of the largest fluvial megafans in the Gran Chaco 12 Plain. It is sparsely populated, affected by extreme drought and flood events that cause severe socio-productive 13 problems. This research aims to integrate and improve the present-day hydrogeologic understanding of the system 14 through the first hydrogeological integrated model for the region. The BBSS hydrogeological system would 15 present a relatively simple hydraulic behavior at a regional scale The sedimentary column simplification in four 16 hydrogeological units (HU) represents the fundamental characteristics of the dynamics of groundwater flows, their 17 interconnections and the interactions with surface water bodies, and the atmosphere through direct recharge. Due 18 to the lack of transient data, the hydrogeological conceptual model was numerically tested under a steady-state 19 flow regime. The numerical model was instrumental to test the plausibility of the proposed conceptual model and 20 evaluate the water balance components for the entire aquifer system, highlighting the role of the stream/aquifer 21 interaction as a leading discharge mechanism and the occurrence of flow exchanges between HUs. Thanks to a 22 newly installed monitoring network, transient simulations will follow to investigate the system’s evolution and 23 explore interventions with environmental sustainability criteria.