Baseline of the outcropping Guarani Aquifer System in Rivera and Tacuarembó, Uruguay: Piezometry and Vulnerability

Abstract

The piezometric, water table and vulnerability baseline of the outcropping Guaraní Aquifer System (GAS) in the departments of Rivera and Tacuarembó (Uruguay) is presented. The flow network and chemical composition are essential to understanding underground dynamics and identifying recharge and discharge zones, preferential flow directions, and determining hydraulic gradients. It is essential to analyze its evolution in time and space from the baseline, for the management and protection of the resource. Vulnerability was determined by applying the GOD and EKv methods, obtaining similar results, with areas of high and moderate vulnerability in most of the studied area. The risk of groundwater contamination was determined using the method of Foster & Hirata(34), obtaining high risk for potentially polluting loads from lack of sanitation, solid household waste, irregular settlements, and gas stations, in areas of moderate and high vulnerability. Industrial and mining activity and a cemetery represent a moderate risk in most cases. Having maps of vulnerability and risk of groundwater contamination is essential to identify the most vulnerable areas and implement detailed study, control, and protection tools aimed at conserving and mitigating impacts on GAS.