Interpreting local-scale solute transport in variously structured soil materials Experimental methodologies and modeling approaches

This paper reports the results of research carried out to establish the possibility of using TDR technology in measuring breakthrough curves of anion tracers such as chloride and bromide. The test conditions adopted refer to the case of undisturbed porous media with bimodal porosity under saturated-unsaturated conditions and to a liquid phase of assigned chemical characteristics. The BTCs were measured with vertically installed TDR probes. Interpretation of signal impedance was carried out in similar fashion to Kachanosky et al. (1992) so as to obtain estimates of the minimum impedance load Z0. The measured BTCs were interpreted to estimate transport parameters by using a two-parameter convective-dispersive model. Finally, a sensitivity analysis of the hydrodynamic dispersion parameter as related both to the average pore water velocity, v, and TDR measurement errors was performed.