2011 Volume 67 Issue 2 Pages I_521-I_532
This paper presents advective-dispersive solute transport processes using a random walk particle tracking approach in upscaled stratified aquifers. An upscaling of hydraulic conductivity distributions is conducted not only for the idealized stratified aquifers but also for an aquifer in a field where the profile of hydraulic conductivity distributions in a vertical direction was measured. The macrodispersivities in corresponding aquifers are estimated using temporal and spatial moments based on breakthrough curves at control planes and spatial distributions of particle crowd, respectively. It is shown that the difference of macrodispersivity attributes to the nature of temporal and spatial moments in the evaluation of a travel distance of particle swarm. The results indicate that the tailing of particle traveltimes depends on the degree of upscaling, although upscaling has a substantially low impact on the macrodispersivity estimates and median traveltimes of particles reaching a control plane. Moreover, particle transfer between layers and its stochastic modeling employed in random walk particle tracking have an effect on the increase of transverse macrodispersivity with the increase of travel distance.
