If you have a fixed boundary outfall condition in your model and want to prevent reverse flow when you run your simulation the best way is to use the Hot Start files to fill up the links and nodes at the start of the simulation.
1st Step: Turn off the DWF inflow so that ONLY the flow from outfall enters the network. Use the Process Models in Run Manager to turn off and turn on the Dry Weather flow.
2nd Step: Run the simulation first SAVING a Hot Start File using zero initial node depths and link flows.
3rd Step: Save and Use Hot Start Files until the initial and final volume in your Network stays the same.
4th Step: Check the Initial and Final Stored Volume in the output text file
5th Step: Check to see if you nodes are stable by using a Junction Group Graph
6th Step: Now Run the Simulation with flows turned an and the network will start out with the Boundary Condition depths and stable flows
