HR: 1330h
AN: H42D-1108    [PDF]
TI: EFFECTIVE SOIL HYDRAULIC PARAMETERS IN HETEROGENEOUS SOILS
AU: * Mohanty, B P
EM: bmohanty@tamu.edu
AF: Texas A\&M University, Department of Biological and Agricultural Engineering, College Station, TX 77843-2117 United States
AU: Zhu, J
EM: jzhu@cora.tamu.edu
AF: Texas A\&M University, Department of Biological and Agricultural Engineering, College Station, TX 77843-2117 United States
AB: The effective soil hydraulic parameters of the areally heterogeneous soil formation are derived by conceptualizing the heterogeneous soil formation as an equivalent homogeneous medium and assuming that the equivalent homogeneous soil will approximately discharge same total amount of flux and produce same average pressure head profile in the formation. As compared to previous effective hydraulic property studies, a specific feature of this study is that the derived effective hydraulic parameters are mean-gradient-dependent (i.e., vary across depth). Three widely used hydraulic conductivity models were employed in this study, i.e., the Gardner model, the Brooks and Corey model and the van Genuchten model. We examined the impact of parameter correlation, boundary condition (surface pressure head) and elevation above the water table on the effective saturated hydraulic conductivity and shape parameter. The correlation between the saturated hydraulic conductivity Ks and the shape parameter $\alpha$ increases the effective saturated hydraulic conductivity, while it does not affect the effective $\alpha$. The effective $\alpha$ is usually smaller than the mean value of $\alpha$, while the effective Ks can be smaller or larger than the mean value depending on no correlation or full correlation between Ks and ƯA fields, respectively. An important observation of this study is that the Gardner and the van Genuchten functions resulted in effective parameters, whereas it is difficult to define effective parameters for the Brooks Corey model since this model uses a piecewise-continuous profile for hydraulic conductivity.
DE: 1836 Hydrologic budget (1655)
DE: 1866 Soil moisture
DE: 1869 Stochastic processes
DE: 1875 Unsaturated zone
SC: Hydrology [H]
MN: 2003 Fall Meeting