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

Hydraulic Jump in Sequential Check Dam Modelling

Hydraulic Jump in Sequential Check Dam Modelling

Hydraulic Jump in Sequential Check Dam Modelling

I would like to model a trapezoidal channel with three sequential check dams.

I am using this BMP for peak rate and volume control.

Channel Slope = 0.06 ft/ft (average of the three)
Width= 2 ft
Sides = 4:1
Depth = 2 ft
Height of Check Dam = 1.50 ft

Section L = 90 ft; 180 ft; 180 ft (upstream to downstream)

I have this routed in HydroCAD: Reach > Pond > Reach > Pond > Reach > Pond with each reach having it's own drainage inflow.

I have the check dams modeled as a broad-crested weir in each pond. Flow overtops each of the check dams, and flows to the downstream reach.

My question: Is there a way to see the elevation of the hydraulic jump in the downstream channel to ensure the elevation remains within the section?

Thanks in advance, file is attached if that helps.

RE: Hydraulic Jump in Sequential Check Dam Modelling

A HydroCAD reach is only intended to model normal Manning's flow. If you have more complex reach flow conditions, including tailwater or a hydraulic jump, you should use a different modeling approach.

In many cases you can simply omit the reach and model pond-to-pond, which will preserve the tailwater capabilities of each pond and it's associated outlet devices. (All pond outlets are tailwater-sensitive)

For additional details please see www.hydrocad.net/checkdams.htm

Peter Smart
HydroCAD Software

RE: Hydraulic Jump in Sequential Check Dam Modelling

Modeling hydraulic jumps (if that's indeed what you're trying to model) requires software that can calculate gradually varied flow profiles. HEC-RAS, really. I'm not convinced that's what you have, though. It sounds more like you just have three weirs, backwatering each other.

If you're not worried about the gradually varied flow profile through your ditches, model all three as ponds.

Hydrology, Drainage Analysis, Flood Studies, and Complex Stormwater Litigation for Atlanta and the South East - http://www.campbellcivil.com

RE: Hydraulic Jump in Sequential Check Dam Modelling

Thank you, gentlemen for the replies. This was to satisfy a reviewer. I ultimately just modeled the ponds in series, and did the math by hand. The "jumps" were negligible.

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


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