Water Flow in Layered Soils With Sloping Surface

An analytical solution is derived for a two‐dimensional soil with a sloping surface under steady and water‐saturated flow conditions. The soil was assumed to consist of several layers, each horizontally stratified. The lower layer was assumed to extend to a great depth. Each layer was considered anisotropic in nature where the hydraulic conductivity in the vertical (κ) and the horizontal (ξ) directions are dissimilar. Potential and stream functions are obtained and several flow nets are presented for two‐layered soils with varying degrees of anisotropy. The range of values chosen was $\xi =(1/25)\kappa -\xi =16K$ and equivalent hydraulic conductivities for two soil layers $(K_1/K_2)$ were 1:1, 1:10, and 10:1. The results illustrate the significance of the degree of anisotropy of each soil layer on the water flow pattern, the relative flow rate, and the volume of water passing through individual soil layers. The presence of an anisotropic lower layer did not influence the relative flow rate entering (or leaving) the soil. Moreover, for most cases, the location along the soil surface which separates seepage into and out of the soil was not influenced by the degree of anisotropy of the infinitely thick lower layer.