EVALUATION OF SIMPLIFIED METHODS FOR DETERMINING UNSATURATED HYDRAULIC CONDUCTIVITY OF LAYERED SOILS.

The simplified field method of L. R. Ahuja et al. (1980) for determining hydraulic conductivity as a function of soil water suction, K(S), and the simplified field method of P. L. Libardi et al. (1980) for determining hydraulic conductivity as a function of soil water content, K( theta ), were compared with the instantaneous profile method, to evaluate their suitability for estimating hydraulic conductivity of layered soil. The Ahuja method worked well on coarse and fine-textured soils and complex soil profiles with stratification. The Libardi method worked well on coarse and fine-textured, homogeneous materials and homogeneous parent materials underlying stratified soil materials. A calculated matching value (K//o) was used with the Libardi method.