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Hydrodynamic Dispersion During Unsteady, Unsaturated Water Flow in a Clay Soil
Author(s) -
Smiles D. E.,
Gardiner B. N.
Publication year - 1982
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1982.03615995004600010002x
Subject(s) - dispersion (optics) , water flow , soil water , chemistry , salt (chemistry) , soil science , chloride , mineralogy , geology , physics , optics , organic chemistry
When a 10 ‐1 M calcium chloride (CaCl 2 ) solution was absorbed by a calcium‐saturated clay soil in which both the water content, θ, and solution salt concentration, C , were initially low, it was found that both θ and C were uniquely defined by the distance divided by the square root of time. The “salt front” did not, however, coincide with the piston front that would exist given perfect displacement of the water initially present in the soil by the water being absorbed. The effect was attributed to a water layer of a thickness about 9Å at the clay surface, which was inaccessible to the anion. Examination of the salt balance indicated that there appeared to be no restriction on the entry of the CaCl 2 into this soil when compared with the water, and an analysis using material coordinates and a constant dispersion coefficient permitted reasonable prediction of the solution salt concentration profile if the inaccessible water was taken into account.