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

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