HR: 1330h
AN: H32A-0528    [PDF]
TI: Quantifying the Macroscopic Hysteresis Effect on Solute Transport in a Heterogeneous Sand Packing
AU: * Rossi, M
EM: michela.rossi@ito.umnw.ethz.ch
AF: ITOe-Swiss Federal Institute of Technology, Grabenstr. 11a, Schlieren, CH-8952 Switzerland
AU: Ursino, N
AF: IMAGe-University of Padua, Via Loreadan, 20, Padua, I-35131 Italy
AU: Lehmann, P
AF: ITOe-Swiss Federal Institute of Technology, Grabenstr. 11a, Schlieren, CH-8952 Switzerland
AU: Fl\"{u}hler, H
AF: ITOe-Swiss Federal Institute of Technology, Grabenstr. 11a, Schlieren, CH-8952 Switzerland
AB: Under unsaturated conditions, water flow and solute transport in a soil material depend on the characteristic relationship between matric potential, water content and hydraulic conductivity. Due to pore size effects, these relationships can be hysteretic, i.e. dependent on preceding drainage and wetting processes. In porous media composed of different materials, an additional hysteresis phenomenon can be observed at the macroscale: it affects the permeability of the boundaries between the different materials and therefore the mass transfer through them. We performed solute transport experiments for different wetting and drainage conditions in a sand tank containing a heterogeneous structure composed by many layers of three sandy materials. Our purpose was to evaluate the effect of macroscopic hysteresis. For this reason we measured the water flow velocity, water content, spatial moments and the reactor ratio for several flow conditions. Being the total transport volume composed by unequal amounts of different sands, we also evaluated for each of them this amount. Some of the measured quantities showed a hysteretic behaviour and they can be indicators of the efficiency of the diffusion through textural boundaries.
DE: 1899 General or miscellaneous
SC: Hydrology [H]
MN: 2003 Fall Meeting