HR: 0800h
AN: H31D-0417    [Abstracts]
TI: Estimation of Moisture-Dependent Anisotropy in Effective Unsaturated Hydraulic Conductivity and Moisture-Retention Curve Using Spatial Moments of Moisture Plumes.
AU: * Yeh, T J
EM: yeh@hwr.arizona.edu
AF: The University of Arizona, Department of Hydrology and Water Resources, John Harshbarger Building 1133 E. North Campus Drive , Tucson, AZ 85721 United States
AU: Ye, M
EM: Ming.Ye@dri.edu
AF: Desert Research Institute , Division of Hydrologic Sciences, Desert Research Institute 755 E. Flamingo Road, Las Vegas, NV 89119 United States
AU: Khaleel, R
EM: Raziuddin_Khaleel@rl.gov
AF: Flour Government Group, P. O. Box 1050, Richland, WA 99352 United States
AB: We have developed a new approach that uses spatial moments of three-dimensional snapshots of a moisture plume under transient flow conditions to estimate the three-dimensional effective unsaturated hydraulic conductivity tensor. The evolution of the spatial first moment in the vertical (z) direction of a moisture plume is used to determine the vertical velocity (Vz) of the center of the plume. This velocity is then related to the gravity term, dKz(theta)/d(theta), of the moisture-based Richards' equation and thus, the vertical unsaturated hydraulic conductivity can be derived. Afterwards, the rate of changes of the second spatial moments in the x, y, and z directions of the plume are related to the water diffusivity tensor (Dx, Dy, and Dz). Assuming that Dx=Kx/C, Dy=Ky/C, and Dz=Kz/C relations, where C is the moisture capacity term, we solve for Kx, Ky, Kz, and C. Application of the new approach to a field experiment yields an effective unsaturated hydraulic conductivity tensor that exhibits moisture-dependent anisotropy. The effective hydraulic conductivities appear to be consistent with laboratory-measured unsaturated hydraulic conductivity data from small core samples; they also reproduce general behavior of observed moisture plume at the site. Finally, potential applications of the approach to laboratory- and field-scale problems, in conjunction with recently advanced geophysical survey tools, are discussed.
UR: http://www.hwr.arizona.edu/yeh
DE: 1829 Groundwater hydrology
DE: 1866 Soil moisture
DE: 1869 Stochastic processes
DE: 1875 Unsaturated zone
SC: Hydrology [H]
MN: 2004 AGU Fall Meeting