Analysis of Recharge in Anisotropic, Layered, Saturated‐Unsaturated Soil

Abstract

A numerical investigation of artificial recharge in multilayered, anisotropic, unconfined porous media is performed for radial flow configuration. The numerical studies, carried out with a saturated‐unsaturated flow model, include the simulation of experimental observations previously documented. The numerical analysis considers the effects of the initial depth of saturation, source geometry, anisotropy as well as material property, and the ratio of equivalent hydraulic conductivity between layers. Once the geometry of the flow region is fixed, the shape of the flow domain and the quantity of flow are determined for any multilayered isotropic‐anisotropic system. For the control series of two cases studied, free‐surface locations closely match the experimental observations. The recharge zone configurations are evaluated by determining the source aspect ratio. In multilayered anisotropic systems, a higher degree of anisotropy results in a greater inflow and a higher position for the free surfaces, when the degree of anisotropy is greater than one. When the recharge is to be accomplished by an infiltrometer, steady‐state flow occurs after a substantial amount of time. This study indicates that the ratio of percent increase in flow rates and percent increase in infiltrometer radii approaches unity.