Siphoning Water Through a 24" Pipe

There's a siphon big enough to drive a truck through 20 miles from my house in Arizona. It carries water in the Central Arizona Project.

As long as the level of the outlet stays below the surface level of the water being siphoned, it should work.

How expensive? No clue.

Agree with Lyn

Automatize it -- time with low tide .

Fill the Syphon from an overhead reservoir or using a small pump.And have a compressed air tank to operate the valve .

Automatize to open the motorized Flap/Butterfly valve WHEN down stream level is low enough.

It is only a 24"pipe and air operated full bore Butterfly valve.

Most effective - yet lowest cost-and fastest drainage OUT

I think you may run into some issues with priming a pipe that size and getting it to stay primed for such a small elevation change.

Personally if I was dealing with a 0 - 2 foot or thereabouts difference I would just go standard culvert and flap gate route. It may cost a bit more but you don't have to fight with setup priming and whatnot every time you use it.

I just siphoned the pool out. Luckily it's on a hill. Every time it rained, I had to do it again, to keep water off the cover. I thought about an automatic siphon. As far as I know, the inlet pipe curves as low as possible, and then up, below the desired level. Then it goes up and over the dam. The exit has to be below the inlet, but curve up to maintain a full siphon tube. When the level goes above the top of the exit, which is the desired level in the target area, siphon is started, automatically. As long as the level in the inlet is above it's top, the siphon should drain the area.

Otherwise, getting a siphon this big started would be a bear, I imagine.

I saw a device like this in a fish tank. It maintained a level in the tank which was receiving salt water from the river. An overflow would have allowed fish and stuff to get out of the tank.

If the priming is done properly so that there is no air entrapped in the pipe, any amount fo water can be taken out. May be some way to keep the pipe always flooded will ensure that siphon works. As long as outout pipe level is below the inlet pipe, it works

The pipe that is utilized for a siphon should be chosen on the basis of its ability to withstand negative pressures and not letting air leak in.

You might like to consider an "inverted syphon" instead. No difficulty in priming and you can have the opening triggered by a float attached to the seal on the inlet side.

How many culverts/flaps do you already have? What is the fall to them?

You may be limited in water removal purely by the ability of the water to cross flow the fields.

(Note that an inverted syphon could be located further into the paddock and thus provide greater avacuation potential.)

With the drop you have and the gauge of the pipe, I would assume a Vortex would be created causing air to intake and stop your siphon.

Maybe multiple smaller pipes would be a better idea? Start one of the smaller pipes off with a small jacking pump, run a small feeder to the second and so on until all pipes are primed and siphoning.

Cheers Glenn

How many of these:

1. Aluminum Siphon Tubes - Empire Irrigation Product Lines
   
2. 
   plastic irrigation siphon tubes available shapes and sizes ...

equal a 24" pipe. Plastic ones would be easy to cut and stretch.

Whatever you do, DO NOT excavate through that levee....don't breathe on it, do pee on it, and don't spit on it! LOL Seriously, breaching it will bring the US Army Corps of Engineers to your drop step in a hurry, and they will be extremely displeased with you. And most likely you will be fined very heavily and held liable for any and all reconstruction repair costs!!!!

Go with an inverted siphon only if you can avoid the above.

Signed,

the Capt. (who formerly served at the USACE NO District Offices).

Good point. More than good point....grin! There might be other considerations...like, Some levees are designed to have a roadway on top of them, and a siphon might be considered to be a road hazard.

I assumed that if he has permission to install a check valved culvert, then why not an inverted siphon? Is this whole exercise an attempt to get around a standard installation which is, once in a while, not quite good enough? I will assume this is the case. In which case, a standard siphon would keep him out of trouble.

Do you suppose that if the siphon was to be inserted into shallow sumps on both sides of the levee, it would eliminate the problem of loss of prime every time the tide went out?
A sump on the outflow side would allow room to install a simple check valve to eliminate the backwash the levee was built to prevent....

I like the idea of an "automatic siphon...but at some point, the water level must rise higher than the highest point of the bend for those to work...and that is not going to happen in THIS application.

Something which may help...

I remember seeing a demonstration as a young man which I believe could be relevant.

A local water utility was looking into a stormwater drain overflowing during heavy rains. It flowed through a large culvert and the water backed up when it hit the side of the culvert and caused it to overflow causing the localised flooding. The sides of the culvert caused the water to create eddies which interrupted the flow into the culvert pipe (a large pie approx 4ft dia?).

They did some modelling to investigate possible solutions. They built a scale model & tried several options which they showed us with actual water flow.

They put in a second pipe (i.e. 2 pipes of the same size), they tried a much larger single pipe, but the other thing they tried, and which was successful, was to streamline the approaches to the existing pipe. This eliminated the turbulence caused by the water when it hit the surrounding flat vertical surfaces around the opening of the culvert pipe, and assisted the water to increase in velocity as it approached the pipe & thus increased the flow capacity. This was the successful solution.

They were able to achieve a higher flow rate simply by streamlining the approaches to the culvert pipe, and it flowed better that 2 pipes or a significantly larger one.

Hope this helps.

What "OLDTECHNEWTOYS" saw 50-60 years back was demonstration of just that : Streamlines Venturi effect in an open channel-

OP's problem is different; Of Time and Tide and Costs

Siphon is The Answer-- with automated discharge valve+land side flap check valve .

"Old Tech New Toys " indeed .

As old as Roman aqueducts

"50-60 years back"... How old do you think I am??? Only 56 yrs young!

re your comment - "OP's problem is different; Of Time and Tide and Costs".

I would respectfully dissagree...

QuentinGreen states - "During extreme weather conditions (heavy rains/hurricanes), I can't remove the water fast enough. I am comparing the cost of additional culverts w/flap gates (about $4,000/structure) versus siphoning the water."

So he is considering additional culverts, which is exactly what one of the options was in my example.

I see his post as saying that if he can remove the excess water fast enough (say, by inrcreasing flow in existing culverts) then additional culverts or the siphoning option may not be required.

" WWW.AZEEMO.COM " I think this will be helpful website for engineering undergraduates.

It has complete engineering projects for all departments & has both free & priced projects with low prices.

Hope you enjoy it.

<...have any idea as to the cost?...>

There are commercial considerations, which will be facility-specific and commercially sensitive information. It is unlikely to be able to find meaningful information in a global engineering forum such as CR4.