Comparison Between Well Known Empirical Models forEstimation of Saturated Hydraulic Conduductivity from Grain Size Distribution Curves

   Abstract:
      In this research five empirical models including Hazen, Shepherd, Kozeni-Carman, Fair & Hatch and Alyamani & Sen for calculating the saturated hydraulic conductivity (K) of soils from particle size distribution curves in respect to the field measured values are examined. Sand, lomay sand, sandy loam, silty loam and loam types of porous media are considered in this study. For each type of soil, ten sets of soils data such as Field measured K values and particle size distribution curves are extracted from UNSODA public domian soil database. Then the calculated saturated hydraulic conductivity from every empirical models for each sample set is compared with the measured K in the field. The results indicate that for all the soil types examined in this research, the Shepherd empirical models for immature soils is the most reliable predictor of saturated hydraulic conductivity from particle size distribution curve. Also, the results of analysis reveal that empirical model of Fair & Hatch seems the worst estimates of the hydraulic conductivity of granular porous media.