The Dispersion tab is on the MODFLOW Layer Groups dialog box.
The Dispersion tab is only visible if the Dispersion package in MT3DMS is selected.
The Dispersion tab is used to specify the transverse dispersivity ratios in the horizontal (TRPT) and vertical (TRTV) directions and the diffusion coefficients for each layer (DMCOEF) in a layer group. Longitudinal dispersivity is defined on a cell-by-cell basis using a data set (Required|MT3DMS|Longitudinal_Dispersivity). The dispersivity and diffisuion coefficients help determine the movements of solutes.
