StormCAD: resetting HGL at manholes

Question

Our local entities require that if the computed HGL is below the soffit of the upstream pipe at a manhole that the HGL gets reset to the upstream pipe soffit to continue the calcs. Can StormCAD reset the HGL under these conditions? Similar to fixed conditions at an outfall

Scott Kampa · Answer

Hello Greg, 
 StormCAD will reset the HGL to rim elevation of a node if that node is overtopping. See this link for details: Why is the HGL reset to the rim elevation for flooded structures? 
 While it will not reset due to other conditions, a profile through the subsurface network can let you see where the system may be surcharging or overtopping, which will help with decision making for the sizing of a system. 
 Regards, 
 Scott

Jesse Dringoli · Answer

Do you have any other details on why this needs to be done? I do not recall ever hearing of this standard before. 
 Here are some possible solutions: 
 
 At the locations where the HGL needs to be reset to the crown/soffit, use an outfall with user defined tailwater. Meaning, you would break the system into segments separated by the locations where this condition occurs. 
 At the locations where the HGL needs to be reset to the crown/soffit, use the "absolute" structure loss method and adjust the headloss value until the HGL at the upstream conduit is equal to the crown/soffit. When conditions change in the model you would need to adjust.