extraction of model parameters for reactive solute transport

Rock material is common in the construction of hydraulic structures. in the present study, to the aim is to examine the reactive solute relationships for transport and degradation processes through the rockfill media. by applying the analytical solution of reactive transport, the 1st to 3rd theoretical temporal moments have been extracted, consequently by applying two methods of curve fitting and temporal moment matching, the coefficients of dispersion and degradation have been exploited. two rock diameter, two operating discharges and five instantly injection mass have been used as the variables of experiments. the ec sensors with operation software were installed inside the rockfill media and then the experimental breakthrough curves with intervals of 4 seconds have been extracted. it is concluded that both methods are suitable for application of transport and degradation processes inside the media. it was found that by increasing inflow discharges, pore velocity, and media diameters the dispersion coefficient decreases and with a decrease in media diameter or with increase in injection mass the decay rate decreases. the sensitivity analysis on the derived moment equation and also skewness coefficient equation indicated that the velocity and degradation are the most and less effective parameters on the moment equations respectively.