Simplified Procedure for Unsaturated Flow Parameters

Abstract

Problem statement: The unsaturated hydraulic conductivity K(θ) and Soil Water Characteristic Curve (SWCC) for saline soil or soil directly contacted with saline water are not permitted using several apparatus to determining. Approach: A simplified method to determine K(θ) and SWCC by using simple apparatus is presented. Using the proposed numerical model with the van Genuchten equations and inverse calculation for K (θ) and SWCC to produce the best fit of this model calculation to the experimental cumulative capillary flow in dry soil columns. These are found by an optimization procedure which adjusts the parameters of K(θ) and SWCC. In addition, the resulting SWCC from the model was used to evaluate the K(θ) for the Gardner equation. Results: Values of saturated hydraulic conductivity K_sat for the van Genuchten equations were lower than those based on the Gardner equation. The K_sat values of dense soil were nearly overall lower than loose soil. Conclusion: Good agreement (R² value) was obtained in the SWCC and K_sat values from the experiment and those calculated from the van Genuchten and Gardner equations this suggests that the simplified method provides a useful means of determining unsaturated flow parameters.