I am doing a dam breach in series with an unsteady state HEC-RAS model.
When run with a high flow storm event (PMP), both dams breach correctly.
When run with a lower flow storm event (SDF), the model becomes unstable when I breach the downstream structure. The only difference between the PMP and SDF models is the lateral inflow, the dam breach parameters (Breach plan data), and the computation interval required to run the model.
The SDF plan runs fine when the "Breach This Structure" is unchecked in the Breach Plan Data, but the model goes unstable and crashes when I check the box to "Breach This Structure" in the Breach Plan Data.
I have searched high and low for an explanation of why, but have come up empty handed. Does anybody have any ideas of why this could be?
I am using HEC-RAS version 5.0.0, but have also tried it in version 5.0.3 with the same results.