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Solute and water movement in unsaturated soils
Author(s) -
Barnes C. J.
Publication year - 1989
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1029/wr025i001p00038
Subject(s) - soil water , hydraulic conductivity , front (military) , water content , water flow , adsorption , porous medium , nonlinear system , flow (mathematics) , chemistry , soil science , environmental science , porosity , mechanics , geology , geotechnical engineering , physics , oceanography , organic chemistry , quantum mechanics
Chromatographic theory of competitive solute movement through porous, reactive soils with nonlinear adsorption isotherms is extended to conditions of unsteady flow in the unsaturated zone under gravity. By treating water content as an extra solute component, equations governing coupled movement of solute and water through reactive soils under gravity are shown to be a special case of those governing competitive solute movement, leading to a quantitative description of the coupled movement of the water and solute fronts through a soil column. When one solution displaces another at a different concentration and water potential in a reactive soil, the solute and water front splits up into two distinct subfronts, separated by a region in which both concentration and potential are constant. Each subfront is characterized by a region in which water content and concentration vary in a predetermined manner, according to certain functions (characteristics), one of which must remain constant over each subfront. Only in certain simple cases will solute concentration and water content vary independently of each other. The case when the hydraulic conductivity depends on solute concentration is explicitly considered.