×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Contact US

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Coupled pond mystery flow

Coupled pond mystery flow

Coupled pond mystery flow

(OP)
I'm running HydroCAD 8 and am hitting a snag.  I have two ponds, each about 1 square mile in size, that are connected by a 48" pipe.  I am proposing a new structure in the downstream pond that will have an invert 10' above the connecting pipe.  When I select the higher invert as a starting elevation, I start to have problems with the flow.

I need to assign the same starting water level to the upstream pond as the downstream, since they're connected.  Stor-Ind routing didn't give me the error for tailwater, but I think the tailwater does have an impact.  DSI and Sim Route show 130 cfs leaving the upper pond, but the summary shows no water going through the culvert (even if I model a reverse flow).

My concerns are that the stage discharge table shows heavy flows starting to occur 2' below my starting invert elevation.  This combined with the culvert not showing any flow happening has me wondering if I'm asking HydroCAD to do a function that it can't handle.  Or have I missed the obvious???

RE: Coupled pond mystery flow

The stage-discharge report does not include the (variable) tailwater effects, but these are incorported in the routing calculations when you use DSI.

Make sure you set the starting elevation in both ponds.  As long as there are no warning messages, the results should be valid.  If you do have problems, you can send the file to HydroCAD support.

Also consider: If the interconnection between the ponds is large in comparison to the final (higher) outlet, then the two ponds will always be equalized, and are more easily modeled as a single pond, ignoring the interconnecting pipe.

RE: Coupled pond mystery flow

(OP)
I ended up running the upstream pond with a starting elevation using stor-ind and a fixed tailwater equal to the starting elevation in the downstream pond.  Then I compared that to sim-route results with both ponds at the same starting elevation.  The results were pretty close in terms of water surface elevations, so I just took the more conservative one.  I am curious that the stor-ind did not show any warnings and the sim-soute indicated potential backflow.  Thanks for the info.

RE: Coupled pond mystery flow

The software will always generate a warning message if tailwater is present and you need to switch to another routing procedure.  Start with Storage-Indication and check the messages.  If there is tailwater, you should generally use DSI rather than SimRoute.  SimRoute is inherently less stable, and has advantages only for reversing flows.  Please see www.hydrocad.net/simroute.htm

If you still have questions please email your file to HydroCAD support.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members! Already a Member? Login


Resources

Low-Volume Rapid Injection Molding With 3D Printed Molds
Learn methods and guidelines for using stereolithography (SLA) 3D printed molds in the injection molding process to lower costs and lead time. Discover how this hybrid manufacturing process enables on-demand mold fabrication to quickly produce small batches of thermoplastic parts. Download Now
Design for Additive Manufacturing (DfAM)
Examine how the principles of DfAM upend many of the long-standing rules around manufacturability - allowing engineers and designers to place a part’s function at the center of their design considerations. Download Now
Taking Control of Engineering Documents
This ebook covers tips for creating and managing workflows, security best practices and protection of intellectual property, Cloud vs. on-premise software solutions, CAD file management, compliance, and more. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close