Pond Boss Forums INTRO New Forum Member Introduction Pond Siphon System

Hello ya'll. I'm new here. I am building a 1/8 acre pond 5' deep. I have been reading about a pond siphon system that will bottom drain the "dead water" or whatever. I have read that the outlet end should be 4' lower than the inlet end. That will be impossible for me. The bottom of my pond is at 2015 elevation which is the same as the "normal" water level of a nearby creek that I plan on draining into. Since my pond is 5' deep, the water level is at 2020 elevation. My question is, If I put my inlet end at 2016 elevation (1 foot off the bottom) and my outlet end at 2015 elevation, will it work at all? That's only 1 foot of drop over a distance of about 70 feet horizontally. or. Would it work if my outlet end is below water in the creek? In other words, would the creek water at my outlet stop the pond water from flowing?

kevinb,

Putting the siphon outlet under water WILL NOT hurt the siphon action.

One of the reasons siphons fail is due to air entry at the outlet working back up to the crest of the siphon. (That is why they frequently show an upturned elbow at the outlet so the end of the pipe is always "full" of water.)

The 4' lower rule of thumb is due to the fact that water flowing through pipes always loses a little pressure due to friction.

It would be difficult to say exactly how much lower your outlet pipe needs to be in your exact scenario. However, if your pipe sizing estimate falls between two different pipe diameters, I would recommend selecting the larger diameter. The larger pipe will have smaller frictional pressure losses and should sustain a siphon for a longer period.

Finally, is the main purpose of your siphon to drain the pond, or to just regulate the water level while new water is entering your pond by drawing more stagnant water off of the bottom?

I speculate that your siphon would probably operate while the pond is full due to the depth of water over the inlet. At some point as the pond level gets lower, your siphon may fail before draining the pond down to the level of the inlet pipe.

(That is low value "internet" advice since we can't see the exact situation for your siphon.)

How high does your siphon have to go at the crest of the pipe?

Good luck on your pond project!

P.S. A 1/8th acre pond is pretty small. Depending on your purposes for draining, you might be better off running in a 3" drain pipe and purchasing a small trash pump?

FishinRod, Thank you very much for answering my question.

The main purpose of my siphon is to regulate the water level. It would rise 4' to the crest of the pipe before falling 5' to the outlet. Maybe 6 or 7' now that I know the water level of the big creek will not disturb the outlet.

I have an artesian well that flows about 10 gallons per minute that I will pipe into the pond. My understanding is that artesian water has no dissolved oxygen so I am thinking to also pipe in some water from a small creek that I think would be highly oxygenated.

I have a sump pump that I used for pumping out the spring water while I was digging. That would definitely pump out the bottom water but I don't know how much that would raise my power bill each month.

Those are all really good ideas. I will probably use all of them. I'm not completely sold on the piping water in from the creek idea because of introducing other species yet. The other species that is in the creek is rainbow trout. I don't know if I am willing to pipe some trout into my bass/bluegill pond. That pipe would have a screen but I'm sure trout eggs could fit thru that screen.

My well is 4' higher than the pond and I really like the idea of pumping some bottom water out right before each rain storm. Thank you so much.

Here's one more question involving acidic water and lime. Does it make any sense to lime the pond if the water is constantly being replenished thru the pipe inlets and the pipe outlet? It seems like the limed water would just flow out as un-limed water is flowing in. I tested my well water and also the creek water and they are 5.4 pH.

Yes, you should lime the pond and you will most likely need to keep replenishing the lime as needed. The closer to a pH of 7.0 the better it is for the fish and other living organisms in the pond. Just like growing plants, when the pH levels move further away from 7.0 the slower things grow because it's harder for them to uptake nutrients.

IF there are ONLY Rainbow Trout in the stream and it would be legal to pump that water into the pond, I would. Any RBT that would survive and make it in the pond would be great bass food.