Comparison of Hydraulic Conductivity Estimation using Falling Head and Mini Disk Infiltrometer in Gypsiferous Soil

Abstract Hydraulic conductivity (K) was calculated using falling head (FH) and Mini Disk Infiltrometer (MDI) for 15 Gypsiferous soil. In this study the hydraulic conductivity was predicted by basic infiltration rate (BIR) and using two methods, Wooding-Gardner (W-G) and van Genuchten-Zhang (V-Z). Hydraulic conductivity was measured using a falling head permeability test, and the results were compared to the expected values. A statistical analysis (t-test) was performed to show the significant differences between the two methods and the falling head. The results showed high agreement between (K) values estimated by (FH) and (BIR) for different gypsum content, the results showed that Both methods did not succeed in estimating the hydraulic conductivity for different gypsum content. Values derived from (W-G) method are exaggerated and the values derived from the (V-Z) method are very low compared to the values derived from (FH).