Abstract

This study delineates the actual hydrogeochemistry and the geological evolution of an unconfined coastal aquifer located in a lowland setting in order to understand the drivers of the groundwater salinization. Physical aquifer parameterization highlights a vertical hydraulic gradient due to the presence of a heavy drainage system, which controls the hydrodynamics of this coastal area, forcing groundwater to flow from the bottom toward the top of the aquifer. As a consequence, relict seawater in stable density strat- ification, preserved within low permeability sediments in the deepest portion of the aquifer, has been drawn upward. The hydrogeochemical investigations allow identifying the role of seepage and water– sediment interactions in the aquifer salinization process and in the modification of groundwater chem- istry. Mixing between freshwater and saltwater occurs; however, it is neither the only nor the dominant process driving groundwater hydrochemistry. In the aquifer several concurring and competing water– sediment interactions – as NaCl solution, ion-exchange, calcite and dolomite dissolution/precipitation, oxidation of organic matter, and sulfate bacterial reduction – are triggered by or overlap freshwater–salt- water mixing The hyper-salinity found in the deepest portion of the aquifer cannot be associated with present seawater intrusion, but suggests the presence of salt water of marine origin, which was trapped in the inter-basin during the Holocene transgression. The results of this study contribute to a better understanding of groundwater dynamics and salinization processes in this lowland coastal aquifer.

Autore Pugliese

• Fidelibus Maria Dolores

Tutti gli autori

• Giambastiani B.M.S. , Colombani N. , Mastrocicco M. , Fidelibus M.D.

Titolo volume/Rivista

JOURNAL OF HYDROLOGY

Anno di pubblicazione

2013

ISSN

0022-1694

ISBN

Non Disponibile

Numero di citazioni Wos

Nessuna citazione

Ultimo Aggiornamento Citazioni

Non Disponibile

Numero di citazioni Scopus

23

Ultimo Aggiornamento Citazioni

2017-04-23 03:20:56

Settori ERC

Non Disponibile

Codici ASJC

Non Disponibile