Problem

Why is there a large drop in the hydraulic grade line between a conduit and a node, when using the HEC-22 structure loss method? For example:

Solution

This is related to the exit loss for the conduit.

The exit loss in the HEC-22 method is based on the velocity. If you have a non-plunging profile with a high velocity, the exit loss will be relatively high compared to the headlosses you might see in the structures or the conduit itself. 

For more information on this, please review the HEC-22 3rd Edition manual. 

See Also

Flat hydraulic grade line over nodes for the HEC-22 3rd Edition Energy Method