Nonreactive solute transport in variously structured soil materials as determined by laboratory-based time domain reflectometry (TDR)

The possibility of using the time domain reflectometry technique (TDR) is tested for estimating transport parameters of an inert solute (KCl) in the soil. Undisturbed soil samples underwent steady flow processes in the laboratory in near-saturation conditions. Space/time distributions of the chloride ion concentration were analysed with the two-parameter convection-dispersion model (CD). Conventional nonlinear optimisation algorithm was used for the derivation of the parameter values. Applied to soil samples of different textures and structures, the method supplied satisfactory results, which indicates that the straightforward use of TDR may permit the method to be more widely applied, both in the laboratory and in the field. Research is currently going on to study the spatial variability of characteristic parameters of solute transport. (C) 1999 Elsevier Science B.V. All rights reserved.