Spatial characterization of the seawater upconing process in a coastal Mediterranean aquifer (Plana de Castellon, Spain): Evolution and controls

Abstract

In this contribution, we describe the formation and evolution of the upconing process in a Mediterranean coastal aquifer. The study area has experienced severe salinization over the last 40 years because of intensive exploitation of groundwater. We used historical and current records of piezometric levels and chloride concentrations to trace the development of the salinization of the aquifer. We defined the 3D shape of the saline wedge from the spatial distribution of chloride concentrations and vertical well logs of electrical conductivity using monitoring network data. Upconing first appeared in the early 90s and has continued until the present day. In this study, we examined the intensity of the upconing process. Dry periods and the associated increases in pumping caused the advance of seawater intrusion. The sharp reduction in groundwater withdrawals over the last 10 years has caused the saline wedge to move backwards, although the ongoing pumping and the climate conditions mean that this retreat is quite slow.