Quantification of Groundwater Vertical Flow from Temperature Profiles: Application to Agua Amarga Coastal Aquifer (SE Spain) Submitted to Artificial Recharge

Abstract

The Agua Amarga coastal aquifer has experienced different anthropic interventions over the last 100 years. Since 2008, groundwater abstractions along the coastline to supply the Alicante I and II desalination plants have been combined with artificial recharge. This measure, consisting of seawater irrigation over the salt marsh, has reduced the impact on the piezometry and surface ecosystems. The study of the effect of this measure on groundwater flow is addressed by applying an inverse problem protocol to temperature profiles monitored in a piezometer located inside the recharge area. Information on monthly seawater irrigation volumes, rainfall, and average air and seawater temperatures have also been gathered as input data to quantify vertical flow. An upward flow component for the period 2010–2022 that varies between 2 × 10−9 and 7.5 × 10−7 m/s has been found. These values decrease near the surface, where the flow is mainly horizontal.