عنوان مقاله [English]
Soil saturated hydraulic conductivity (Ks) is one of the main parameters in water and solute transport studies in soil and irrigation and drainage projects designs. So, knowledge about the Ks spatial distribution pattern has great importance. The aim of present study was to predict spatial distribution pattern of Ks in the experimental field of Sistan Dam, Zabol University, using different interpolation methods. For this purpose, a set of 113 single ring Beerkan infiltration experiments were carried out over the study area in a grid of average distance about 80 m. The Ks was obtained through Beerkan calculating algorithms, BESTslope, BESTintercept and BESTsteady. The relative fitting errors were 5.19% and 9.39% for BESTslope and BESTintercept algorithms, respectively, that are satisfactory. The interpolation methods were compared using evaluation criteria such as the weighted determination coefficient (ωr2) and standard error (SE). Based on the results, the spatial correlation of Ks was moderate and it had the exponential structure. The results showed that Log Kriging (LOK) achieved the highest ωr2 and lowest SE values for estimating Ks over the study area with a dominant soil textures of loam and sandy loam. However, the difference between LOK and the other interpolation approaches was not significant. Moreover, among the interpolation methods, BESTsteady algorithm, which had the simplest calculating procedure, had the highest precision in estimation. So, according to the results, LOK with an exponential semivarigram model is suggested as the best interpolation method for predicting the spatial distribution of Ks, based on values obtained from the simple and applicable algorithm, i.e. BESTsteady, in loam and sandy loam soils.