×
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!
  • Students Click Here

*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

Jobs

Deep drainage structures

Deep drainage structures

Deep drainage structures

(OP)
Looking for design info. for a catch basin/ drop inlet approx. 30 feet deep, feeding a 42" outlet pipe. This is for a quarry reclaimation plan.  What kind of info. or standard drawings are out there? I seem to see that most standards limit the height to 10-12 feet.  Also, are there any major issues with a water drop of this distance?  
Thanks in advance, Herb

RE: Deep drainage structures

The only thing I see as a problem will be the water hitting the bottom and causing wear in the structure. You will have to reinforce the bottom  and construct a sump also.

Richard A. Cornelius, P.E.
WWW.amlinereast.com

RE: Deep drainage structures

(OP)
Thanks for the reply,  my thoughts too on reinforcement.  Have you got a diagram of the sump you mentioned?

RE: Deep drainage structures

Zebco - I think you are in a realm of design where you will need to come up with the design.  I know that this configuration is not common in my area.  You may be able to put something in the vertical drop to diffuse the water enough to limit the impact at the bottom.  I first thought of a device at each pipe joint that would push the water to one side and then back (zigzag).  The other thought I had is similar to dick's but use a manhole base with a 3-foot sump filled with 6-12" riprap.  Just some thoughts.

RE: Deep drainage structures

zebco,

Is there another way to drop the water? (i.e could you install a few sections of sewer and manholes to drop the flow 30').

I would have a few things that come to mind with a direct 30' drop.

1) As gbam and dicksewerrat have outlined, scour would be an issue at the botom of the structure. Especially if you require a 42" outlet. I'm not sure a 3' sump would be enough given the drop.

2) Maintenance access. A 30'drop would require (depending on design standards in your area), 1-2 safety platforms within the structure. I would assume that you would want access given the drop. With the flow that would be entering the structure, you would have to provide a safe access for maintenance staff to the bottom of the structure.

3) Custom Structure Design. The structure that you would be looking for would have to be structurally designed and likley not something that could be obtained via a catalouge. Groundwater pressure, soil pressure, internal forces, etc would come into play with a structure like this.

4) Outlet. There would be quite a bit of turbulence at the bottom of the structure, it may also be beneficial to look further at the 42" outlet for erosion and scour d/s.

Hope this helps.

RE: Deep drainage structures

No drawing. But if you put a 3-4 ft sump below the outlet invert and line the bottom with granite paving blocks,  it should last until you retire. The water in the sump will slow down the water and the granite will protect the cncrete sump bottom. Do you know the flow depth in the 42"? You may want to have the lip of the sump at or above the flow line in the 42".

Richard A. Cornelius, P.E.
WWW.amlinereast.com

RE: Deep drainage structures

2nd the recommendation for a granite invert.

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

RE: Deep drainage structures

had another thought....

I've seen vortex drop structures for sanitary applications, which may work for this. May be something to look into.

RE: Deep drainage structures

(OP)
Thanks guys, since I'm in a quarry, I think I'll create a sump/dissapator pad of granite in the invert.

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