Zero Velocity and HGL

Question

Hello, 
 I have a horizontally laid pipe network that runs in a flooded stage set by weirs. Since StormCAD does not have the option to place weirs I have set a tailwater (at the weir crest plus the head) to run my analysis. The results I am getting from the program show zero velocity and a constant HGL for the majority of the system. 
 Beside optimizing he pipe network (using smaller pipe sizes), is there anything in the base calculation options that I can change? Am I missing anything? 
 Thank you in advance.

MPachlhofer · Accepted Answer

Armando, 
 
The problem is that you have large system flow times, which is what determines the intensity. Flow is based on the rational formula for StormCAD Q = CIA, so a small intensity will provide a small flow which in turn provides a low velocity. 
 
There are some calculation options that can help with this. One is "Ignore travel time in carrier pipes?" This allows for the elimination of the flow reductions that otherwise occur as a result of the system time. The other option is to set "Correct for partial area effect?" to True. This allows for StormCAD to use the largest flow entering the node. 
 
For a more information on these please see this wiki article: 
 
 communities.bentley.com/.../26029.where-can-i-find-the-definition-of-a-property 
 
Regards, 
Mark