title: Seawater intrusion in karstic, coastal aquifers: Current challenges and future scenarios in the Taranto area (southern Italy).
abstract: Mediterranean areas are characterized by complex hydrogeological systems, where management of freshwater resources, mostly stored in karstic, coastal aquifers, is necessary and requires the application of numerical tools to detect and prevent deterioration of groundwater, mostly caused by overexploitation. In the Taranto area (southern Italy), the deep, karstic aquifer is the only source of freshwater and satisfies the main human activities. Preserving quantity and quality of this system through management policies is so necessary and such task can be addressed through modeling tools which take into account human impacts and the effects of climate changes. A variable-density flow model was developed with SEAWAT to depict the "current" status of the saltwater intrusion, namely the status simulated over an average hydrogeological year. Considering the goals of this analysis and the scale at which the model was built, the equivalent porous medium approach was adopted to represent the deep aquifer. The effects that different flow boundary conditions along the coast have on the transport model were assessed. Furthermore, salinity stratification occurs within a strip spreading between 4km and 7km from the coast in the deep aquifer. The model predicts a similar phenomenon for some submarine freshwater springs and modeling outcomes were positively compared with measurements found in the literature. Two scenarios were simulated to assess the effects of decreased rainfall and increased pumping on saline intrusion. Major differences in the concentration field with respect to the "current" status were found where the hydraulic conductivity of the deep aquifer is higher and such differences are higher when Dirichlet flow boundary conditions are assigned. Furthermore, the Dirichlet boundary condition along the coast for transport modeling influences the concentration field in different scenarios at shallow depths; as such, concentration values simulated under stressed conditions are lower than those simulated under undisturbed conditions.
authors.affiliation: Land Lab, Dipartimento di Scienze della Vita, Scuola Superiore Sant'Anna, Via S. Cecilia, 3, 56127 Pisa, Italy; Consorzio Interuniversitario per la Fisica delle Atmosfere e delle Idrosfere (CINFAI), Piazza N. Mauruzi, 17, 62029 Tolentino, MC, Italy; Dipartimento di Scienze della Terra "A. Desio", Università degli Studi di Milano, Via L. Mangiagalli, 34, 20133 Milano, Italy. Electronic address: g.defilippis@sssup.it.
authors.forename: Giovanna
authors.initials: G
authors.lastname: De Filippis
authors.affiliation: UC Davis, California.
authors.forename: Laura
authors.initials: L
authors.lastname: Foglia
authors.affiliation: Consorzio Interuniversitario per la Fisica delle Atmosfere e delle Idrosfere (CINFAI), Piazza N. Mauruzi, 17, 62029 Tolentino, MC, Italy; Dipartimento di Scienze della Terra "A. Desio", Università degli Studi di Milano, Via L. Mangiagalli, 34, 20133 Milano, Italy; Istituto per la Dinamica dei Processi Ambientali (IDPA-CNR), Via Torino, 155, 30172 Venezia Mestre, VE, Italy.
authors.forename: Mauro
authors.initials: M
authors.lastname: Giudici
authors.affiliation: Department of Civil Engineering, California State University, Chico, CA, United States.
authors.forename: Steffen
authors.initials: S
authors.lastname: Mehl
authors.affiliation: Laboratorio di Idrogeofisica e Stratigrafia per i Rischi Naturali, DISTeBa, Università del Salento, Via per Monteroni, 73100 Lecce, Italy; Geomod srl, Spin-off of DISTeBA (Università del Salento), Via per Monteroni, 73100 Lecce, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Margiotta
authors.affiliation: Laboratorio di Idrogeofisica e Stratigrafia per i Rischi Naturali, DISTeBa, Università del Salento, Via per Monteroni, 73100 Lecce, Italy; Geomod srl, Spin-off of DISTeBA (Università del Salento), Via per Monteroni, 73100 Lecce, Italy.
authors.forename: Sergio Luigi
authors.initials: SL
authors.lastname: Negri
keywords: Groundwater management scenarios; Karstic coastal aquifers; Mediterranean area; Saltwater intrusion