DEVELOPMENT OF PROBABILITY DISTRIBUTIONS FOR SOIL- WATER RETENTION CHARACTERISTICS

Abstract

A method is presented for developing probability density functions for parameters of soil moisture relationships of capillary head [yr(A)] and hydraulic conductivity [K(0)]. These soil moisture parameters are required for the assessment of water flow and solute transport in unsaturated media. The method employs a statistical multiple regression equation proposed in the literature for estimating [yr(0)] or [K(0)] relationships using the soil saturated water content, residual water content and the percentages of sand and clay. In the absence of known statistical distributions for either [ijr(0)] or [K(6)] relationships, the method facilitates modelling by providing variability estimates that can be used to examine the uncertainty associated with water flow or solute transport in unsaturated media.