Review of Empirical Equations of Estimating Saturated Hydraulic Conductivity Based on Soil Grain Size Distribution

Knowledge of hydraulic conductivity is essential for many problems involving water flow and pollution transport in soils. A variety of field and laboratory techniques have been developed to directly measure the unsaturated hydraulic conductivity. In this research, 25 set of soil samples with sand texture have been used. The results showed that among seven empirical formulae (Hazen, Kozeny-Carman, Breyer, Slitcher, Terzaghi, USBR and Alyamani & Sen), the Slitcher formula predicted Ks, saturated hydraulic conductivity, better than other formulae with 0.671 R; 6.08 RMSE; 5.06 MAE; 20.75% RE & 1.393 DT and the Breyer formula estimated Ks, with largest prediction error.(Abstract)