Comparison of alternative models for simulating solute transport in heterogeneous soil at large scale

This study compared five different models for simulating solute transport in a 1250cm long and highly heterogeneous soil column. The five models were: the convection-dispersion equation(CDE), two-region model(TRM), convective lognormal transfer function model(CLT), fractional advection-dispersion equation (FADE) and continuous time random walk(CTRW). The results indicated that the CDE, CLT and FADE were all unable to describe the anomalous measured BTCs adequately, and FADE provided somewhat better simulation results at the tailing part of the anomalous BTCs than CDE and CLT. The TRM and CTRW provided nearly similar good simulation results except that the modeling results of CTRW were somewhat larger than those of TRM at the tails of the BTCs. With respect to CDE, CLT and FADE, both TRM and CTRW were better to capture the full evolution of the measured BTCs at different travel distances, especially for the early and long tailing parts. Moreover, the degree of anomalous transport behavior in the heterogeneous soil column was reduced with transport scale, and TRM and CTRW detected this trend adequately. To compare the applicability of the TRM and CTRW in evaluating more complex solute transport issues in heterogeneous soils, the strengths-weaknesses analysis of them was presented in this study.

Comparison of alternative models for simulating solute transport in heterogeneous soil at large scale Academic Article