How can I model a siphon and spill-over using EPA swmm

[onyeuko]

I have a combined sewage drainage project in which it has been decided to cross a canal underneath the floor bed(thus using a system of siphon). The project is to convey a media discharge of 7.40l/s and a maximum of 30.0l/s. It is decided to divert any discharge above this figure(30.0l/s) through a short pipe(spill-over) as to discharge into the canal because at this level of discharge(during rainfall), the sewage must have been diluted to the extent that it is safe to discharge into the canal.
I would like to know which object (or how) in EPA SWMM , I can model the siphon and the control system which will allow only up to the discharge of 30.0l/s to flow into the system, as such which will enable me to model the condition under which I can discharge the excess into the canal as spill-over.
Teddy

 

[tsgrue]

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I may not be understanding your description correctly. If I am, it seems you could use a hydraulic divider node to split flows over 30 lps. Depending upon the siphon control, you could also include an orifice, pump, or weir in sequence if needed. If I didn't follow you correctly, please post a diagram/graphic to relate what you are describing.

Are you using SWMM5?

Hope that helps...

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tsgrue: site engineering, stormwater
management, landscape design, ecosystem
rehabilitation, mathematical simulation

http://hhwq.blogspot.com

 

[onyeuko]

Yes, I am using SWMM5
You understood the first part of the issue(the spill-over) very well, but the siphon part-no. The siphon part is not in series with the spill-over but is included in the system as an undergroud passage as not to disturb flow through the canal. The pipe supplying the sewage, the spill-over pipe and the pipe conveying the sewage(the siphon part) to the treatment plant, all meet in an accumulator(a tank).
Note: I have tried to load the drawing but was not able. Seems the forum does not have facility to load drawing or to send attachment. If there is, please tell me how so that I can load the drawing for you to see
Teddy

 

[tsgrue]

.

For the upload:

1. See the "Attachment" option under the message text box for posts.

2. Try the format listed in "EDITING TIPS" for "To include an image in your post".

3. Check out the following post for step-by-step instructions: "pasting images within a post" at
"

http://www.eng-tips.com/viewthread.cfm?qid=194031&page=6",

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.


tsgrue: site engineering, stormwater
management, landscape design, ecosystem
rehabilitation, mathematical simulation

http://hhwq.blogspot.com

 

[onyeuko]

I am up-loading the relevant drawings as requested.It is in bmp format but copied to micro-soft word(as such a word document)The link is:

http://files.engineering.com/getfil...-6192510ddc66&file=Drawing+for+forum.doc1.doc

Thanks
Teddy

 

[onyeuko]

tsgrue, try this to see if you can download from the attachment(as in my last upload):
Download the attachment without opening directly from the site but first save on you desktop, document or the like.
After saving, then open the file as saved. I tried it and it worked
Teddy

 

[tsgrue]

.

Okay, I downloaded the file this time. It was rather blurry/lo-res, but I think I could make it out. It would seem you could use a hydraulic divider node to split flows over 30 lps and use an orifice, pump, weir, or some combination of these to model the siphon. remember that these are just modeling elements to mimic the siphon function, so you just want the operating curve to be equivalent to a siphon even if the elements are totally different.

Are you using a siphon due to solids concerns? Could you just have sealed consuits/manholes and drive the with pressure flow? It looks like from your profile that such would work, but I can't make out the head difference across the channel.

Try coming up with a SWMM5 model and then sending me the input file (*.inp).

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tsgrue: site engineering, stormwater
management, landscape design, ecosystem
rehabilitation, mathematical simulation

http://hhwq.blogspot.com

 

[onyeuko]

I am sorry I could not reply much earlier. It is due to work pressure. Yes, I used divider to split the flow over the quantity admissible(revised to 75.0l/s-which is to pass through the siphon)and the excess is to be diverted through a discharge pipe that discharges into the canal. I modelled the whole system but found out that it is either the whole sewage is discharging through the siphon or through the discharge pipe which means that I did not get it right. I am sending the file as modelled with SWMM5 to you as to make a controll. If the file did not correspond with the former one that I sent to you, please do not border as the whole thing including the variations are aimed at the same thing-Modelling the siphon, the divider etc(note that the basic plan and section drawings are same for all cases)
Teddy

 

[onyeuko]

Also view the following attachment. It may be different from the one sent earlier but the concept is the same.The section is as the one sent earlier(refer to the previous drawings on attachmnet

http://files.engineering.com/getfil...6192510ddc66&file=Drawing+for+forum.doc1.doc)

Teddy

 

[tsgrue]

.

I looked over your model. You should be able to insert a storage unit and a pump to represent the wet well and siphon. You might need to use control rules for the siphon depending upon the detailed design. Alternately, you could probably define a flow/rating curve for the diversion link (again, depending upon the specific wet well and siphon design). You could also have some other combinations of hydraulic nodes/links as well. I think your basic setup is fine and you'll just need to try out the best options for your particular case. If you get stuck after trying these options, post again and I'll try to help.

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tsgrue: site engineering, stormwater
management, landscape design, ecosystem
rehabilitation, mathematical simulation

http://hhwq.blogspot.com

 

[onyeuko]

I do not follow with your suggestion that I should insert a storage unit and a pump to represent the wet well and siphon. I do not understand how to position them as such will be grateful if you should give me a sketch. I had already concluded the design using manual calculations but I want to learn on how to do it with the soft ware.
Teddy