INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

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.

Jobs

Inverted Siphon For Storm Pipe

Inverted Siphon For Storm Pipe

(OP)
I've got a project where the outflow storm line (24") is draining a 2 acre commercial site. The contractors uncovered an existing water main that is conflict with the storm drain.

The City will not allow this waterline to be adjusted around the storm pipe. Unfortunately there is not another viable option for the site storm connection.

My thought is to install an inverted siphon under the water main. Basically have the 24-inch pipe duck under the existing waterline, then connect into the City curb inlet(discharge point).

Has anyone designed one of these before. I plan on installing an access MH just upstream of the waterline crossing. I'm not sure what hydraulic losses I might consider for such a system. The HGL of the site system should create enough pressure get through the siphon and into the point of connection.

I thought it might also be practical to install a second bypass line over the waterline for good measure.

Understandably that when the storm surge is over, there will be some residual water left in the pipe, like a grease trap in a house. In this part of the country, the soils are mostly clay, so infiltration of residual water might not work to well. In other words, we might have to live with that portion of the siphon holding some water.

Any thoughts or ideas? Much appreciated.

RE: Inverted Siphon For Storm Pipe

I've done what you describe before Dredger. It's especially common in Florida where everything is flat anyway. But CVG is right, your first option should be to go with a conflict structure, and it sounds like your situation is perfect for one.

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

RE: Inverted Siphon For Storm Pipe

inverted siphons are a maintenance nightmare for storm drains. almost guaranteed, they will fill up with sediment at the worst possible time. most agencies will not allow them. if you do it, make sure the velocity through a siphon is high enough to move the sand and gravel through. a conflict manhole may collect some debris, but unlikely to fill with sediment.

RE: Inverted Siphon For Storm Pipe

In our jurisdiction, a conflict structure would not be allowed for a storm drain crossing a potable water main.

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!


Resources


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