Estimation of Unsaturated Soil Hydraulic Properties Using Analytical and Inverse Methods Based on Disc Infiltrometer Measurements

Estimation and modeling of non-saturated hydraulic properties of the soil is an effective approach to accelerate and facilitate studies on the movement of water and salts in the soil. In this paper, an inverse solution estimation method was used to analyze the results obtained by disk infiltrometer tools. Also, Wooding analytical method and Hydrus-1D software were used to simulate infiltration values and hydraulic properties. In this regard, four lysimeters were used and infiltration experiments were carried out at suctions of 15, 6, 3 and 1 cm. Also, pressure data were recorded by four tensiometers installed in the lysimeters. Finally, the results of the inverse solution method were compared with the Wooding method. The results showed that the inverse solution method was generally in good agreement with the Wooding analysis method. The inverse solution method estimated the unsaturated hydraulic conductivity values close to Wooding method at low suctions, but the estimated values were greater 12% than the Wooding method with increasing suctions.