Victor Vilarrasa1, Jesus Carrera2. 1. Earth Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720; Soil Mechanics Laboratory, School of Architecture, Civil and Environmental Engineering, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland; victor.vilarrasa@upc.edu. 2. Groundwater Hydrology Group (GHS UPC-CSIC), Institute of Environmental Assessment and Water Research, Spanish National Research Council, 08034 Barcelona, Spain.