Multidimensional Infiltration: Points, Furrows, Basins, Wells, and Disks

Abstract

AbstractMultidimensional infiltration theory continues to be an area of soil physics research dominated by the works of J.R. Philip. The point source of these endeavors was his landmark paper in 1966. Here in our contribution honoring John Philip, we first discuss the multidimensional, similarity‐solution antecedents that were queried by him nearly 30 yr ago. We then list the new theoretical developments contained in this comprehensive treatise on multidimensional flow into unsaturated soil. Next we comment on the three steady‐state sequels derived by J.R. Philip, P.A.C. Raats, and R.A. Wooding, especially in relation to the experimental studies they spawned. Experiments initially began with attempts to verify directly the various multidimensional flow theories. But experimental procedures soon came to use, in an inverse sense, these theories to permit measurements of the hydraulic properties of field soil. The disk permeameter, currently a widely used device, employs multidimensional theory. In a variety of ways, disks are used to infer the hydraulic properties of field soil in the pressure potential range close to saturation. However, here we propose a method by which the disk permeameter can be used to deduce in situ the nonlinear adsorption isotherm that holds for the transport of reactive chemicals through soil. We demonstrate this proposal by using in the inverse sense of parameter identification, not an analytical description, but rather a two‐dimensional numerical simulation of the flow of water and transport of solute away from a surface disk maintained at a given pressure potential, and some fixed concentration of reactive solute.