I have a healthy one acre pond at 3,000' elevation in California, max depth of about 12'. It has catfish, bass, and bluegill in it.

Other than rain runoff, the water source is water that is piped in from a stream diversion. The piped water flows most of the year, and there is a spillway/outlet on the exact opposite side of the pond.

A relative wants to move the outlet to be sited very close to the water source and is determined to do it. From where the water comes in, the outlet would only be maybe 1/15 the way around the pond. So the water inlet, and outlet, will in the future be sited very close together.

I don't know much about pond health, but I am concerned about maybe creating a stagnant area on the opposite side of the pond? It seems that having the outlet so close to the inlet will at least introduce this possiblity?

Ideas?

Why does he want to do that? Does he have final say or do you?

And a hearty welcome to the Pond Boss family. I believe you will find the experience useful as well as entertaining.

I'm not so certain that relocating the outlet presents a huge problem; and the effort and expense in doing so might provide some benefits IF the relocated discharge-outlet is fashioned as a pipe-conduit that is somewhat larger in diameter than the fill-pipe AND is extended to the deepest depths of the pond. This arrangement would potentially benefit the pond by constantly discharging the deepest (poorest quality) water as it is displaced by diverted water from the stream. An emergency overflow would still be needed to accomodate heavy rain/snow-melt run-off that exceeds the new discharge-pipe's capacity.

My relative is intending to make this change soon unless there is evidence of causing any harm.

I didn't fully explain earlier that there is an existing spillway at the opposite end of the water source, and the new outlet, sited near the water source, is also a spillway. So only surface water is going through either outflow.

btw, the water source diverted from the stream has very little silt, as it goes through various screens and collection boxes before getting to the pond.

That's the point I was attempting to make. If water must be discharged, it is better to discharge water from the deepest areas of the pond instead of surface-water. In doing so, the pond should "circulate" water vertically (top to bottom) rather than horizontally, as it is now.

That's great information-- just what I was hoping for and thanks!!

Q- if there is no existing piping in place, as in my case, what are some methods to go about discharging water from the bottom of the pond yet still keeping the pond level stable?

Hey, I'm just a concept-guy in this case
Putting the concept into practice will test your ingenuity.
DISCLAIMER: I've never witnessed nor attempted this idea (?); but I'm imagining something along the line of non-perforated flexible conduit for constructing the interior drain-pipe extention.
The highest elevation of the drain-pipe's lowest interior surface will dictate the pond's static level, except during heavy inflow-events.

If considering this project, keep the below image in mind (and Google any unfamiliar terms for their definitions).


EDIT: Hmmm. Just thought of something. DON'T extend the exterior section of the drain-pipe (as depicted in the above illustration). Doing so (in the absence of an air-vent at the drain-pipe's highest elevation) would potentially create a siphon-effect that could drain the pond until it dropped to an elevation that was even with the end of the discharge-pipe.

Maybe I am missing something.

If the pipe is at the bottom of the pond on one end, and is run above the water level and up and over the spillway, wouldn't the water have to run uphill in the pipe to get over the spillway level?

I understand that you could start the water flowing by using some sort of siphon, but it would be impractical for me to constantly have to re-start a siphon as the water level fluctuates?

You'd want to avoid any sibilance of a siphon for multiple reasons, including that which you stated.

In effect, the drain-pipe would be routed through the existing or planned overflow-structure, and "embedded" in such a manner that the normal volume of stream-diverted water could only flow through (not around) the pipe. The highest elevation of the drain-pipe's interior-base would correlate to the desire pond-level (<read this sentence very slowly ). As the pond rises above that elevation, water would discharge through the drain-pipe - exactly as it does when it exceeds the low-point of the existing over-flow structure.

In this cut-away, the red line represents "the highest elevation of the drain-pipe's interior base". This scetch isn't technically correct, since discharge wouldn't occur until the pond's level rose above the red line.

In hydrological terms, the effect would be the same as the thoretical sketch below; which shows water exiting the top of a vertical pipe (positioned on the backside of the containment-berm), whereas the top-opening of the pipe shares the same elevation as the pond. (Once again, the diagram isn't exactly correct, since discharge wouldn't occur until the pond's level rose above the pipe-opening's elevation).

Two more illustrations of the overflow interface. Hope they make sense.

I gotta ask Kelly, what did you use to sketch it out?

Crayons, on my monitor. Duh!!!



Seriously, MS Digital Image Suite 9 (software).
With practice, it's a fairly quick and easy process. I used a stock-image of a representative pond-cutaway, and simply overlaid (drew in) the details I wanted to illustrate.

Has anyone ever tried this method before? With success or not?

Also, would this be the next best alternative to aeration when electric and wind power is not available? Granted it is not adding O2, but it seems like it would circulate the water.

A standard siphon with an air vent pipe on top will do both. It can be used to siphon if the air vent is closed with a cap or it can keep the water level at a set height just like Kelly drew. We use several types and they all work. You can go to Pond Dam Piping's web site and see a bunch of them.

See this http://www.ponddampiping.com/syphon1.html

O.K. Remember that the next time we get together, I'll bring my crayons and see how it works on your monitor!

Thanks (in all seriousness)

Eric: you're taking the fun out of complicating a relatively simple concept.
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@Scott: Sharpies work too! Give it a try, on YOUR monitor. You can show me the results at the next conference.

Kelly: I wanted to use a siphon system on my recent pond rebuild, but didn't have sufficient elevation change (below the dam) to make it work. Instead, I used a modified version of what you're talking about, utilizing 6" PVC. The top fitting on the discharge stack is not glued, so I can change elevations by simply adding or reducing height. The pond is now at pool level, and everything seems to be working just fine. I still have to pour a concrete "splash" apron below the discharge. Look toward the very end of the photos.

http://s1179.photobucket.com/albums/x398/critterville/?albumview=slideshow

Some of the water I have is under pressure- about 42psi. Currently such water just dumps out of a pvc pipe and splashes into the water at the shore.

Would it be better for pond health to pipe this water to the bottom of the pond so that "new/fresh" water is introduced at the bottom?

@Woodcrafter: Your system (below) is almost exactly what I was attempting to describe. The only difference is that it drains bottom-water through the dam rather than routed through an existing overflow structure.


42 psi at the pipe-opening? What is the pipe's diameter? >to get an idea of the pipe's flow-rate..
Depending on the answer, it might be possible to create a bottom-diffuser using water forced through a vertically-oriented venturi-device.
I've never seen or tried it; just an idea.

The pipe is 6" pvc at a maximum flow of about 300 gpm.

At the shore of the pond, I am using about 50gpm of the 300 gpm for another use. This water becomes gravity flow runoff after this use.

The remaining water I have available (max 250 gpm) is reduced from 6" down to 4" pvc under pressure of about 42 psi. That is the water I could pipe to the bottom of the pond if that provided any benefit compared to just dumping it in at the shoreline.

Jetting water through the interior of larger cylinder creates a low-pressure region at the opposite end of the discharge (venturi principle). The volume of water that exists the larger cylinder is a multiple of the volume that is jetted under pressure.
In theory, jetting the incoming water through a deeply submerged and vertically oriented venturi-structure should create a fair amount of vertical circulation.


I'm not sure if the next idea would work; but it might be possible to attached a small tube (that extends above the surface) to the low-pressure region of the submerged cylinder. Depending on the pressure-differential, the tube "should" allow inducted surface-air (bubbles) to exit the cylinder's top in unison with the vertical upwelling of water.


250 gpm (=15k gal/hr = 1.1 ac/ft per day) is a lot of water for such a small pond. If your pond EVER has the ability to stratify, then I'd suggest using the incoming water to prevent such occurances.

I'm now curious to know if anyone has ever tried similar methods to utilize the benefits of pressurized water-inflows. Or, is this simply a crazy concept?