Pumping to and sihponing from and Impoundment

[rangercap]

Anyone have any experience with the design of a waterline used to pump to AND siphon from and large water storage impoundment?

I have a client who only wants to use only line for both purposes, obviously not at the same time. For air release valves for pumping, I have spec'd manual ball valves for air release maintenance. My concern is with sizing the pipe for 350 gpm up to the impoundment, but then utilizing the same line to siphon back down to a water transfer station. This only one part of a larger overall water trucking operation for shale gas development. The line is approximately 4200LF and has an overall elevation change of 400'.

Thanks

Brian

 

[bimr]

You have not detailed the change in elevation that would cause a siphon. There should be adequate pressure as well as flow on the lower sections of the pipeline with the 400' elevation change.

A lot will depend on the profile of the pipeline which you have not presented.

 

[rangercap]

The impoundment we have designed is 35 feet deep. There are no major grade changes in the profile. It is pretty much a continuous grade from the impoundment to the outlet.

Top of berm is 1220'
Bottom of impoundment is 1185'
Outlet at siphon is 820'

Brian

 

[bimr]

Well then, you do not have a siphon. You have a reservoir with a bottom inlet/outlet.

This type of arrangement is common for water systems.

The issue that will be of concern is the high water pressure. You probably will need some type of pressure regulators on the water use points to drop the water pressure down.

I assume that you know that you can not allow water to reverse through the centrifugal pump that is generally used for this application. You should also use a pump pressure controller that will assist the pump startup when operating against the high static pressure.

 

[rangercap]

BIMR - We do have a siphon. We are not drawing from a bottom inlet. Our inlet is at the bottom of the impoundment. We need to go UP over the berm, then back down hill.

I'm simply looking for some information about using one line, instead of two to pump and sihpon. I'll check around elsewhere for more information.

 

[cvg]

siphons have been discussed frequently on the forum. unless you have a particular concern, maybe these previous threads will help

http://www.eng-tips.com/search.cfm?...iphon&t=&h=&searchSite=2&searchArea=1&d=4&s=1

 

[rangercap]

Thanks CVG - I looked through most of those threads and didn't really see what I was looking for.

Thanks for the link - I'll scour them one more time.

Brian

 

[77JQX]

The single pipe is a non-issue to me - that's the way all water storage tanks are. Just guessing, but it seems you're trying to balance the pipe size for filling with the pipe size you'd need to maintain a working siphon - that is, making a single pipe work hydraulically. If this were me, I'd size the pipe for the filling operation, and then throttle the outlet to control the siphon hydraulics. I expect the cost of flow control will be much less than the cost of a parallel pipeline. You'll need to control access to the flow control, because your truckers will want to turn up the flow, causing the pipeline to go vacuum.

I've found plotting the pipeline profile, along with the siphon HGL (plus atm less vapor pressure) to be useful.

 

[cvg]

nailed it