Multi-chemical and isotope approach for studying shallow and deep groundwater interaction in an urban area: The case of Tivoli Plain (central Italy)

Interaction between shallow and deep groundwater flow systems has been investigated by the means of chemical and isotopic tracers in the Tivoli Plain aquifer system (Rome, central Italy). During the last decade an intense activity in the travertine quarries in the Acque Albule basin has caused a significant drop in the water table of the shallow travertine aquifer. A multi-isotope approach was used to have a better understanding of interactions between shallow and deep aquifers, and to improve the knowledge of the conceptual hydrogeological model, which has implications for groundwater management in the Tivoli plain. The hydrochemistry of the travertine aquifer is characterized by a mixing between two end-members related, respectively, to groundwater coming directly from outcropping carbonate aquifers and to groundwater circulating in deep buried Meso-Cenozoic carbonate sequences. 18O and l3C isotope tracers are diagnostic for the geochemical mixing definition. Copyright © 2011 IAHS Press.