Hydrology and Earth System Sciences www.hydrol-earth-syst-sci.net 1027-5606 1607-7938 9 5 2005 10.5194/hess-9-517-2005 http://www.hydrol-earth-syst-sci.net/9/517/2005/ http://www.hydrol-earth-syst-sci.net/9/517/2005/hess-9-517-2005.html http://www.hydrol-earth-syst-sci.net/9/517/2005/hess-9-517-2005.pdf 517 522 2005-10-31 Do effective properties for unsaturated weakly layered porous media exist? An experimental study A. Bayer H.-J. Vogel O. Ippisch K. Roth Institute of Environmental Physics, University of Heidelberg, Im Neuenheimer Feld 229, 69 120 Heidelberg, Germany Interdisciplinary Center for Scientific Computing, University of Heidelberg, Im Neuenheimer Feld 368, 69 120 Heidelberg, Germany In a multi-step outflow experiment we found that a weak heterogeneity within a sand column prevents the estimated effective hydraulic parameters from being unique. We compared vertical water content profiles calculated from these parameters with profiles measured by x-ray attenuation. A layered material model based on x-ray data was able to reproduce the outflow curve and also the water content distribution inside the column. We also calculated effective parameters for the layered model turned upside down and obtained large differences to the set of values of the original sample.