Evaluation of Different Methods for Measuring Field Saturated Hydraulic Conductivity under High and Low Water Table

Abstract

In this research, four methods of in situ measurement of saturated hydraulic conductivity (Ks) including the Guelph permeameter (GP), auger hole (AH), original Porchet (OP), and saturated Porchet methods were compared for a silt loam soil. The representative Ks in a drainage system was also determined as a reference value. The mean values of Ks for the GP, AH, OP, SP, and drainage system methods were 1.18, 1.06, 1.85, 1.18, and 1.08 m d−1, respectively. Furthermore, the GP and OP methods had the highest and lowest coefficients of variation at 42.1 and 24.2%, respectively. The difference in Ks values among all methods except SP and GP and the difference in CV values between GP and OP were statistically significant at the 0.01 level of probability. The direct measurement from the drainage system resulted in Ks values of 0.584, 0.915, 1.019, and 0.915 times that of the OP, SP, AH, and GP methods, respectively. The results of the SP, GP, and AH methods were very similar to that obtained from direct measurement of the drainage system. Results showed that the AH and GP methods are the best methods for measuring Ks in the presence and absence of a water table, respectively, with −1.85 and 9.26% difference, respectively, compared with the reference method. Therefore, in regions with a high water table, the AH method is suitable, and for a low water table, the GP method is recommended.