HR: 1340h
AN: H33A-1370    [Abstracts]
TI: Relationships Among Air-water Interfacial Area, Capillary Pressure, and Water Saturation for a Sandy Porous Medium
AU: * Brusseau, M L
EM: brusseau@ag.arizona.edu
AF: University of Arizona, 429 Shantz, Tucson, AZ 85721
AU: Peng, S
EM: pengs@email.arizona.edu
AF: University of Arizona, 429 Shantz, Tucson, AZ 85721
AU: Costanza-Robinson, M
EM: mscostanza@yahoo.com
AF: Middlebury College, MC, Middlebury, VT 05753
AU: Schnaar, G
EM: gschnaar@email.arizona.edu
AF: University of Arizona, 429 Shantz, Tucson, AZ 85721
AB: The relationships among air-water interfacial area, capillary pressure, and water saturation were investigated for a sandy, natural porous medium. Air-water interfacial areas as a function of water saturation were measured using two methods, gas-phase partitioning tracer tests and synchrotron X-ray microtomography. The tracer-test method provides a measure of effective total (capillary and film) interfacial area, whereas microtomography can be used to determine both capillary-associated and total areas (the latter is the focus of this study). Air-water interfacial areas determined with both methods increased continuously with increasing water saturation. The areas determined with the tracer-test method were significantly larger than those determined from microtomography. The interfacial area-saturation data were combined with capillary pressure-saturation data obtained from water-drainage experiments to examine the relationship between air-water interfacial area and capillary pressure. Air-water interfacial area was observed to increase monotonically with increasing capillary pressure, and then plateau at values that correspond to areas associated with residual water saturation. These results are consistent with previously reported theoretical and computational based analyses of functional relationships between total nonwetting-wetting interfacial area and capillary pressure.
DE: 1866 Soil moisture
DE: 1875 Vadose zone
SC: Hydrology [H]
MN: Fall Meeting 2005