Mass imbalance in transport model (FEFLOW 7.0)

Is export of the rate or period budgets for mass the correct way to assess the imbalance in the mass budget (rather than fluid budget) in FEFLOW 7.0? I seem to be getting very large imbalances (up to 50-100%) and wondered whether I was exporting the wrong data to assess this? If not, then what is the best way to address this imbalance? I am using automatic time stepping - so that leaves refining meshes (either laterally or by layering) around steeper concentration gradients? I have convergent flow fields (pumping from within a stationary plume) rather than the more common in literature source to receptor conceptual model - so presumably a smaller dispersivity would make more sense? Might this make achieving a good mass balance problematic?

Yes, the mass imbalance in the Rate / Period panels is the way to assess the imbalance in the mass budget. In contrast, the fluid imbalance in the Rate / Period panels is the way to assess the imbalance in the fluid budget.

Perhaps the following discussion may help you to reduce the imbalance: http://forum.mikepoweredbydhi.com/index.php?topic=2263.msg5246#msg5246

Thanks Bjorn!