ESTIMATION OF UNSATURATED HYDRAULIC CONDUCTIVITY FROM INFLOW DATA

The double integration method is used to estimate the unsaturated hydraulic conductivity from the retention curve and previous knowledge of the inflow data and of the resistance of the crust. This method has the advantage of being valid regardless of the form of the soil water characteristics. The sorptivity approximation must be carefully chosen to obtain unsaturated hydraulic conductivity regardless of the initial water content. A differentiation procedure leads to straightforward and very accurate estimations of the unsaturated hydraulic conductivity when combined with Brutsaert's sorptivity approximation. Despite its accuracy, Parlange's sorptivity approximation poses some initial difficulties when the initial water content is noticeably different from the residual one.