We have developed an inexpensive and efficient method to measure field-saturated hydraulic conductivity (Kfs) using a scaled transparent cylinder. The cylinder was inserted in sandy soil to visually measure temporal changes in water levels, i.e. hydraulic head H(t), in the cylinder. The infiltration flux density (qs) in the cylinder was obtained using three different methods: ( 1 ) a quadratic or ( 2 ) a cubic equation to fit temporal changes in the hydraulic head H(t), and ( 3 ) a central difference approximation in the hydraulic head H(t). The field-saturated hydraulic conductivity (Kfs) was calculated by multiplying the flux gradient (dqs / dH), cylinder diameter (a), π, and a dimensionless shape factor (G) proposed by Reynolds and Elrick ( 1990 ), to express the effect of three-dimensional infiltration flow. However, the Kfs with the proposed G value overestimated known saturated hydraulic conductivity (Ks) in sandy soil by 10%. So, new relationships between various known saturated hydraulic conductivities (Ks) and dimensionless shape factors (G) were established using a simulation model, HYDRUS 2 D / 3 D Ver3 . 01 , with a falling head infiltration boundary condition. The new procedure with a newly established dimensionless shape factor (G) successfully estimated Kfs in sandy soil using visually-measured temporal changes in water level H(t).
