Comparison of Two-Parameter Vertical Ponded Infiltration Equations

Abstract

Five two-parameter (sorptivity, S, and saturated hydraulic conductivity, Ks) vertical one-dimensional infiltration equations are compared quantitatively over the whole time range from zero to very long times. These equations are Green-Ampt (GA), Talsma-Parlange (TP), Brutsaert (B), Swartzendruber (SW), and Valiantzas (V). The results showed that the cumulative infiltration i (t) predictions of equations B, SW, and V are between the two limit soils characterized by GA and TP equations. Compared with the TP equation, the equations of B, SW, and V showed a maximum discrepancy of 3.8%, 5.6%, and 9.88%, respectively, while compared with the GA equation showed a maximum discrepancy of 14.8%, 11.4%, and 7.8%, respectively. However, the differences among SW, B, and V are lower. The study of cumulative infiltration data of four porous media showed that the S/Ks ratio may be a criterion for the appropriate infiltration equation selection. The S/Ks values for the porous media studied ranged from 2.6 to 136 min0.5. The V equation showed very good prediction of the results in the case of low S/Ks values (coarse-textured soils), while the SW equation in the case of high values (fine-textured soils). Also, the linear form of the V equation was applied for direct estimation of the two parameters, S and Ks, using vertical infiltration data of four porous media with relatively good results (0.980 < R2 < 0.999).