I'm getting flooding at an inlet, but when I run as a culvert, no flooding. Why? In my StormCAD model, a single lateral conduit has an incredible exit loss at a manhole connection.
Our developers have implemented an enhancement to check for this condition and handle it more appropriately. You can get this enhancement by downloading the Select Series 4 cumulative patch or installing the latest version of the software. Directions for how to do that can be found here:
Downloading OpenFlows | Hydraulics and Hydrology Software
If you are unable to apply the Select Series 4 cumulative patch or install the latest version of the software, there are a number of potential workarounds. You could: 1) Set the structure loss method to HEC-22 2nd edition for that node; 2) Lower the invert to prevent the plunging condition 3) Calculate the desired structure loss externally and input that as an "absolute" loss for the node (or estimate a K for the standard method).
What are the differences between the HEC-22 3rd edition and the HEC-22 2nd edition?
Flat hydraulic grade line over nodes for the HEC-22 3rd edition energy method