Assessing the Uncertainties of the Water Budget in the Torrevieja Aquifer (Southeast Spain)

Abstract

The frequent scarcity of water in the coastal aquifers of the Mediterranean areas makes essential the adequate management of groundwater with a good knowledge of the inputs and the outputs of the aquifers. The establishment of the water budget of aquifers is often hindered by uncertainties in the connection with other aquifers and the sea, or the permeability of layers that can disconnect hydraulically parts of the system. In the study of these regions, a common challenge is the lack of information at deep locations or disperse data in time and space that do not allow to provide reliable answers. Under these circumstances, the construction of simplified numerical models simulating groundwater flow can be used to verify or deny different hypothesis. In this study, the characteristics of Torrevieja aquifer (South East of Spain) have been analyzed proposing alternative conceptual models to explain the annual deficit of 4.4 Mm3 between inputs and outputs. The effect of a semipermeable top layer and the differentiation of the aquifer in two parts with distinct recharge sources was tested and compared with the hydrochemical information of groundwater samples to provide new perspectives about the characteristics of this aquifer. This study also shows how to use common hydrogeological tools and information of databases to address the uncertainties in the study of coastal aquifers.