A new model for predicting the hydraulic conductivity of unsaturated porous media

Key Points

• To develop an analytical model predicting unsaturated hydraulic conductivity curves using water retention data and measured saturated conductivity.
• Modified the Childs and Collis-George pore-sequence framework to account for the geometric effects of larger pore sections.
• Derived a computational method to calculate residual water content and extrapolate capillary head data measured over a limited range.
• Evaluated model accuracy against measured data from 45 soils and compared performance to models by Averjanov, Wyllie and Gardner, and Millington and Quirk.
• The proposed analytical model achieved closer qualitative and quantitative agreement with experimental observations across the 45 soil datasets than existing alternative models.
• The derived computational framework successfully estimated residual water content and enabled reliable extrapolation of soil moisture-capillary head curves.