HR: 10:50h
AN: H42C-03    [Abstracts]
TI: Tomographic Measurements of Pore Filling at Infiltration Fronts
AU: * DiCarlo, D A
EM: dicarlo@mail.utexas.edu
AF: The University of Texas at Austin, Petroleum and Geosystems Engineering 1 University Station C0300, Austin, TX 78712-0228, United States
AU: Seale, L D
EM: dseale@msa-oxford.ars.usda.gov
AF: USDA/ARS National Sedimentation Laboratory, 598 McElroy Dr PO BOX 1157, Oxford, MS 38655, United States
AU: Willson, C S
EM: cwillson@lsu.edu
AF: Louisiana State University, Civil & Environmental Engineering Department 3418 Patrick F. Taylor Hall, Baton Rouge, LA 70803, United States
AU: Ham, K
EM: kham1@lsu.edu
AF: Louisiana State University, Civil & Environmental Engineering Department 3418 Patrick F. Taylor Hall, Baton Rouge, LA 70803, United States
AB: For certain porous media and initial conditions, constant flux infiltrations will produce a nonmonotonic saturation profile. This nonmonotonicity is purported to be a cause of gravity driven fingering, cannot be described by standard models of unsaturated flow, and is likely due to the wetting front being sharp at the pore-scale. Here we report micro-computed tomography measurements of the porous medium and measure which pores are filled by water and air at the initial wetting front as a function of flux. We find that at high fluxes all the pores are filled with water; for intermediate fluxes the pores along the edge of the column become unsaturated; and for low fluxes the pores in the bulk of the experimental column become unsaturated. This suggests that the transition between a sharp and diffuse front as a function of flux is abrupt, and that the unsaturated conditions observed at intermediate and higher fluxes are primarily an edge effect of the column.
DE: 1838 Infiltration
DE: 1866 Soil moisture
DE: 1875 Vadose zone
DE: 1895 Instruments and techniques: monitoring
SC: Hydrology [H]
MN: 2007 Fall Meeting