1. Hydrogeology Group, Department of Civil and Environmental Engineering; Barcelona Spain
2. Laboratoire d'Hydrologie et de Géochimie de Strasbourg, University Strasbourg/EOST, CNRS UMR; 7517 Strasbourg France
3. Dipartimento di Ingegneria Civile e Ambientale, Politecnico di Milano; Milano Italy
4. Department of Hydrology and Water Resources; University of Arizona; Tucson Arizona USA