Vol.:(0123456789) 1 3 Environmental Earth Sciences (2018) 77:237 https://doi.org/10.1007/s12665-018-7418-2 ORIGINAL ARTICLE Hydrodynamic analysis of a Mediterranean aquifer system with the use of hydrochemical and isotopical analysis as supporting tools Christos Pouliaris 1,2  · Martha Perdikaki 1  · Laura Foglia 3  · Christoph Schüth 2  · Andreas Kallioras 1,4 Received: 8 November 2017 / Accepted: 12 March 2018 © Springer-Verlag GmbH Germany, part of Springer Nature 2018 Abstract The management of groundwater resources in coastal environments within the Mediterranean basin has become of paramount importance, especially in the light of global changes. A typical example of such a hydrosystem is the Lavrio basin in Greece. This research site involves two aquifer types—granular and karstic formations—that are hydraulically interconnected. Fur- thermore, the proximity to the sea and the abstractions for irrigation and drinking water supply have led to the phenomenon of seawater intrusion. The present study aims at analyzing the hydraulic, hydrological, and hydrogeological conditions of the area by means of hydrochemical and isotopical data interpretation as supporting tools, which will inform and support the development of an integrated conceptual hydrogeological model of the area. Field investigations were conducted in order to collect piezometric and chemical data and use them to retrieve the quantitative and qualitative status of the local aquifer units. New interpretation of an older dataset gave an insight into how the karstic aquifer behaves in terms of hydraulics. The results have also demonstrated that there is a hydraulic connection between the different aquifers and the Mediterranean Sea, while natural recharge was quantified for both aquifer types. Keywords Groundwater resources · Coastal aquifer systems · Seawater intrusion · Isotope hydrology · Groundwater salinization Introduction Land that surrounds the Mediterranean Sea is probably one of the most widely investigated regions in terms of groundwater resources management studies. For example, in Israel, early studies on the use of chloride concentrations in rain and groundwater to assess groundwater recharge were performed (Eriksson and Khunakasem 1969). Later, a variety of methods have been used to investigate the dif- ferent hydrological, hydrogeological, hydrochemical, and hydraulic aspects of the coastal hydrosystems. A number of studies in the region have focused on the impacts of human activities on the natural hydro-environment (Rosenthal et al. 1992; Zilberbrand et al. 2001; Sivan et al. 2005 for Israel, El Banna and Frihy 2009 for Egypt, García-Pintado et al. 2007 for Spain, Güler et al. 2012 for Turkey), while some others provide insight into the future of water resources manage- ment as rainfall patterns and temperatures are altered due to climatic alterations (Sherif and Singh 1999 for Egypt, Benini et al. 2016 for Italy). The use of groundwater hydrochemical characteristics to evaluate the qualitative status of coastal aquifers has been, and still is, a very popular and effective method of assessing groundwater resources (Grassi and Cortecci 2005; Grassi et al. 2007; Giménez-Forcada et al. 2010; Ghiglieri et al. 2012; Caschetto et al. 2017 for Italy, Rosenthal et al. 1992; Zilberbrand et al. 2001 for Israel, Eissa et al. 2016; Salem * Christos Pouliaris pouliaris@metal.ntua.gr 1 Laboratory of Engineering Geology and Hydrogeology, School of Mining and Metallurgical Engineering, National Technical University of Athens, Heroon Polytechniou Str. 9, 15780 Zografou, Athens, Greece 2 Hydrogeology Group, Institute of Applied Geosciences, Technical University of Darmstadt, Schnittspahnstrasse 9, 64287 Darmstadt, Germany 3 Department of Land Air and Water Resources, University of California Davis, One Shields Avenue, Davis, CA 95616-8627, USA 4 Institute of Communication and Computer Systems, Heroon Polytechniou Str. 9, 15773 Zografou, Athens, Greece