Sedimentation fast in upstream boundary

Dear EFDC,
I have a model of reservoir sedimentation. Why sedimentation in the upstream boundary occurs very fast and big?. Can you explain? Or I either put the upstream boundary conditions? is there a special trick to put the upstream boundary conditions?
Thanks.
DYAH ARI

The most likely reason is that your settling velocity is too high. If you have real TSS values for your loading, and you are not seeing this kind of settling in real life at the incoming boundary condition, then your settling velocity must be the issue.

Dear Kester,
Its mean like calibration process. I must change settling velocity so TSS model as equal as TSS data.
Regards
DYAH ARI