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Journal of Applied Sciences

Year: 2002 | Volume: 2 | Issue: 1 | Page No.: 120-124
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Research Article

Determination of Hydraulic Properties of Soil as a Porous Medium

A.A. Siyal, A.G. Siyal, Z.A. Abro, F.C. Oad, M.A. Samo and N.L. Oad

ABSTRACT

Both soil water retention curve and unsaturated hydraulic conductivity data are often necessary for solving unsaturated flow problems. A field experiment was carried out at the Agriculture Research Experimental Area, Tandojam to evaluate appropriate and time efficient methodologies to determine soil hydraulic properties. The soil profile on which experiment was carried out consisted of clay, clay loan and silty clay soil. Three conventional analysis methods such as instantaneous profile method, Millington and Quirk method, CGA method, and one parameter optimization model MULSTP were applied to calculate unsaturated hydraulic conductivity as a function of soil moisture content [K(Ө)] from the field as well as laboratory data. Instantaneous profile method was used as reference against which the alternative methods were compared. The simplified methods (Millington & Quirk and CGA) were found to show satisfactory results with considerably less effort and the VGM parameter optimization method with MULSTP model was found to yield realistic values of hydraulic conductivity. The VGM parameters known through optimization technique by MULSTP model provided extrapolation of unsaturated hydraulic conductivity close to the Millington and Quirky CGA methods. Having been based on continuous function, MULSTP has the advantage that it can be used for computer simulation of salt and water movement in the unsaturated soils.
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