Evaluation of Pedo-Transfer Functions for Estimating Soil Saturated Hydraulic Conductivity (Case study:Urmia Plain)

Document Type : Research Paper

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Abstract

Saturated hydraulic conductivity of soil, as one of the most important soil physical properties, has special importance in identifying, investigating and modeling of water, solute and pollutants transport in porous media. Despite numerous researches, measuring saturated hydraulic conductivity by direct methods is still costly, time consuming and professional. Therefore, estimating saturated hydraulic conductivity using rapid and low cost methods such as pedo-transfer functions with acceptable accuracy is essential. The purpose of this research was to compare and evaluate 12 pedo-transfer functions which were presented by many researchers to estimate the saturated hydraulic conductivity of the soils. The region studied in this research was a part of the Urmia plain in West Azerbaijan consisting soils of Nazlu, Khodaverdikhan and Golmankhaneh villages. 40 measuring locations were selected randomly. In each selected location, a 30 cm hole was excavated and soil saturated hydraulic conductivity was measured by Guelph permeameter. The excavated soils were used in the lab to determine their easily accessible parameters. The results showed that among the studied models, the Aimrun model had the best estimation for soil saturated hydraulic conductivity. For the mentioned model, the Akaike’s information criterion (AIC) and root mean square error (RMSE) parameters were -130.99 and 0.174 m/day, respectively. The results of the present research, emphasize on the importance of effective porosity application as an effective accessible parameter to increase the pedo-transfer functions accuracy.

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