Pond Routing

[DE Yakr]

As per the HydroCAD Owner's Manual, pond routing assumes basically a "zero-velocity level pool" and "If the velocity approaching the outlet device(s) is significant, pond routing may underestimate the discharge and overestimate the peak elevation and storage of the pond.".
Questions:
1. What would be defined as "significant"?
2. If I modeled pipes (closed drainage) as ponds, wouldn't they all fall within the above statement?

 

[psmart]

You will have to determine what is "significant" based an an evaluation of your specific circumstances. If there is sufficient approach velocity you may decide to adjust (increase) the efficiency of the outlet device. But this is getting into a kinematic routing through the entire structure. (You would need a fluid dynamics program to perform a full analysis.)

Regarding "modeling pipes (closed drainage) as ponds", if you are talking about underground storage in the pipes, this is level-pool storage with zero velocity. The fact that you are using pipes to provide the storage is irrelevant. In this situation the pipes are not being used as an outlet control, so the entire issue of approach velocity does not apply.

Peter Smart
HydroCAD Software

http://www.hydrocad.net