Horizontal Cylindrical Detention

[gadwall]

I am having trouble trying to use the Horizontal Cylinder storage function for a detention facility I am designing. The site has about 9 feet of in elevation. I have two catch basins acting as ponds with no storage in the area of higher elevation. Thus, the culverts for each are on very steep grades(>10%). I have set the grade on the horizontal cylinder to 0.5% so I don't have standing water after a storm event.

I have tried using a vertical orifice to reduce the flow from the system, but I get little or no reduction of flow. The only thing that I can figure out is that the steep grade of the pipe coming into the system is causing the pond to be in a pressure flow situation all of the time. Is there somethin that I am missing? What else can be done to model this situation?

Any and all replies are welcomed.

 

[psmart]

I assume your "pond" is setup something like this:

Storage = Horizontal Cylinder
Outlet = vertical orifice

The orifice should be part of the same pond that includes the cyclinder storage.

Check the pond summary carefuly to make sure everything is setup properly. Are there any warning messages? If so, you need to resolve them. Also review the stage-discharge and stage-storage graphs. Are these correct? If you still have problems, send the HCP project file to support@hydrocad.net

 

[gadwall]

Thanks for the quick reply Mr. Smart. I checked all of the warnings and have tried to correct them. Still had the same issues. I have since scrapped the underground detention for an above ground pond. Above ground pond worked well.

Thank you again for your quick reply. I really enjoy working with your product.

 

[psmart]

There is no reason the underground storage would not work. It behaves just like a normal above-grade pond. If you decide to return to this option, you can send the file to support@hydrocad.net

 

[queque]

A SKETCH OF THE PROBLEM WOULD BE HELPFUL.