Unsaturated hydraulic conductivity from transient multistep outflow and soil water pressure data

In this experimental study, soil water pressure head and transient cumulative outflow measured simultaneously are used to estimate unsaturated hydraulic conductivity functions (Kθ). An alternative method for the direct measurement of K(θ) from transient multistep outflow experiments was adopted. Desorption experiments were carried out for disturbed Yolo silt loam, Panoche loam, Hanford sandy loam and Oso Flaco fine sand columns. The optimized K(θ) values agreed well with the directly measured data for all soils, except the sand. Measured infiltration in a column of the Panoche loam matched numerical results using optimized parameters as determined from a sorption multistep experiment. The addition of soil water pressure head values in the optimization procedure provides unique parameters for the unsaturated hydraulic conductivity functions under these experimental conditions. -from Authors