I need to calculate 1-D contaminant concentration profile along advective groundwater flow against dispersion. In other words, groundwater flow containing low concentrations is towards a region of high concentrations. My goal is to find the advective velocity that provides the best-fit to observed concentrations.
The most relevant literature on such an analytic solution is:
A. N. S. Al-Niami and K. R. Rushton, Analysis of flow against dispersion in porous media, J. Hydrology, 33(1977), 87-97.
My understanding is that the analytical solutions in CXTFIT are for matching column test data, where fluid containing high concentrations is injected upstream; therefore, flow is always along the same direction of dispersion. If that is the case, I won't be able to use CXTFIT for my study. Is my understanding correct?