The inside of the caisson and the steel lid was insulated to minimize the adverse effects of subzero winter temperatures on the instrumentation. A 2.0 m dia. The geologic material was a uniform fine grained post-glacial aeolian sand. The water table was measured at 6.0 m below ground. Fate and Transport of Solutes in Aquitards Solute transport is generally viewed as the net effect of two processes, advection and dispersion.
Advective transport is attributed to the average motion of the fluid.
In processes with only advection as the transporting mechanism, a sharp interface would be maintained between the initial and displacing fluids. The second process, dispersion, causes mixing at the interface between the two fluids. Mechanical mixing is the result of velocity variations within the porous media. Most studies of solute migration in hydrogeologic systems have considered aquifers and the impact of contaminants upon groundwater supplies. As a result, most hydrogeologists have generally assumed advection and mechanical mixing to be the dominant processes controlling solute migration.