Pond Boss Forums GENERAL QUESTIONS Property Projects & Construction Using A Well

They finally put the well in for our new house we're building next to my pond. I'm thinking about trying to use it some to help fill the pond. I was hoping to up grade things a bit to get better flow, but the cost was going to be way more than the wife was going to go along with. I ended up with what I guess is a standard hydrant, I think it is 1" in 3/4" out. What I would like to know is what would give me the best flow to the pond? Just run a 3/4" hose all the way down? Try to up size the hose? Use some 4" corrugated tubing for as much of it as I can? My hydrant is about 200' from the pond, and about 30' higher. The first 70'-80' is pretty much level. I don't want to spend a lot on this until I see if it can truly help my pond. The well guy claims it should flow enough to put 1" in a 1 acre pond, in 24 hours. I have my doubts about that but I will be lucky if my pond is a 1/2 acre when full.
Thanks for any thoughts.

Run the hydrant flat out and see how long it takes to fill a 5 gallon bucket. Then do a little math to see how long it would take to add 27,154 gallons (1 acre-inch) to the pond.

That's if your ground water supply is sufficient for the pump to run that long without sucking sediment or air.

For comparison purposes, our house well will deliver 11 gallons per minute flat out, which would take 41 hours to pump and acre-inch. It will suck sediment out of the (locally depleted) ground water in less than an hour.

Thanks Theo, I'll do the bucket test later today.

I don't know what all the well talk that the guy was saying meant, but the well is 625' deep, he set the pump at about 400' because that was close to the pumps limit and close to the wells max flow of supposedly 40 gpm. He wasn't saying I could pump that much with my setup, but the well it's self could. At first he thought he could do a upgrade for $2,500 and I was going to do it, but when he actually started pricing things out it came to about $4,500 and I said for get it. He said the one hydrant would probably flow about 10 gpm, which my math shows more like 48 hours to put 1" in a 1 acre pond. He did say when the plumber gets my other hose faucets in, I could run a 2nd hose, and while it wouldn't double my flow it would give me a little more and keep the pump from cycling as much.

There are multiple, complex calculations to answer your question.

I will try to knock off some of the simplest parts.

Fluid flow through a pipe generally has a very low pressure drop until you really start pushing the fluid, and then any additional fluid rate significantly increases the frictional pressure drop.

Unfortunately, 10 GPM through 3/4" PVC pipe (for example) is causing a pressure drop of 12 psi per 100' of pipe. However, that is for a horizontal run. When your pipe turns downhill it will start to function more like a siphon - and will reduce the pressure losses.

The frictional pressure loss in the pipe causes some additional problems. First, it will change where your submersible pump is operating on the pump curve. A significant pressure increase to the pump will cause it to pump less fluid, AND it will cost you more electricity per gallon of water pumped.

Just moving up to 1" PVC pipe reduces the pressure drop to only 3 psi per 100' of pipe. However, as suggested above, test what you can do with your system. Another option is to just cobble something together with existing materials you already have available. If you have 150' of corrugated 4" drain pipe, I would run 50' of hose into that, and let the water just run down the large pipe the rest of the way. Just coil it up and put it out of sight when your pond is full. If the rate test at the bottom of that system is significantly less than your rate test right at the tap, then you would need to spend some money and up-size the first 50' of hose.

If you are going to make a permanent solution in that area, I would probably make a changeover at the 3/4" tap and run 1.25" or 1.5" polypipe to the pond.

Bigger questions:

Will your pond usually/mostly stay full due to surface water, and this project is mostly for the initial fill-up (and also later drought insurance)?

If you are frequently going to be pumping well water, then I would look at a better solution. What is the size of the main pump outlet pipe? Do you have ready access to it? For example, is it exposed in a little pump house? If so, I would install a tee there, BEFORE the pipe goes to your pressure tank. Put in full-opening valves at the two tee outlets. When pumping to the pond, shut the valve to the pressure tank - you should still have the contents of the tank available for small household usages.

That set-up will give you maximum water to the pond for your pump set up. However, your submersible pump is almost certainly set up for "household" usage which means it pumps a little, and then shuts down. When filling the pond, you would be utilizing your submersible pump as a continuous-duty pump. Make sure to check with your pump installer, how it will function in that capacity. It may do just fine, if it has a thermal safety shut-off when it starts running too hot (for example). Or your pump guy may tell you to run it only 4 hours on / 4 hours off when filling the pond (for example).

Finally, "household water" is much more valuable than "pond water". I do not think you will enjoy living there if you have to haul water from town to fill a rooftop tank. Hopefully, your water well is tied into a significant aquifer. (The rate at which you can pump water is much more dependent on the geology immediately surrounding the well, than it is on the total size of your aquifer.) You might want to ask you pump guy if any of the household water wells, or agricultural irrigation wells in the area are beginning to run dry.

What is the static fluid level in your water well? It should be in your report. 625' is pretty deep for a household water well. I suspect they did not connect to a single good sand/gravel horizon. Instead they have tied together multiple, small water-bearing horizons.

Good luck on your project! I hope a little bit of what I said may be applicable to your actual set-up and situation.

Thanks FishinRod!
I did the bucket test a couple times today and came up with about 15 seconds to fill the five gallon bucket. I'm taking that as about 20 gpm, at least for a short time.
I haven't seen a report yet, I guess he will give that to the builder ( or me ) after he pays him. He talked like it was a strong aquifer and I shouldn't have a problem running it, but might be best to run when at night when sleeping or when gone to help keep from pressure dropping, and if I do see the flow dropping, to cut back for a while.
Right now I'm just hoping to be able to use the well some now and then. The pond has been close to full but never been completely full. It is close right now, do to a lot of rain the last few weeks. It will be 19' deep when full and is about 17' now. At this level it is dropping about 1.25" per day. I've been talking with TJ and hope to place an order this week for some polymer.

The other consideration to take into account is O2. At that depth, it is highly likely that the water you are pumping out has very little (most likely right around 0) oxygen, so you will want to oxygenate it before it gets to the pond if you already have fish. This can be really easily done by agitation or mixing, you essentially just don't want to run the hose down and pump it in under the surface of the pond. It will oxygenate quickly if you expose it to air first. When I added to mine with a hose last year during the drought, I just sprayed it against some rocks before it flowed down into the pond and didn't have any issues.

Bob,

Glad to hear that your water well is probably going to be "supplemental" for the pond. (That makes me feel a little better!)

20 GPM is way too much flow for a 3/4" garden hose, you will definitely be wasting lots of effort from your submersible pump. (Even a 3/4" tap is a restriction. If they are already going to add a second hydrant, perhaps consider paying a little more and having them match one tap of the hydrant to the same size as the incoming pipe? Extra flow rate available for pumping to a pond, or fighting a grass or house fire is pretty valuable IMO.)

I also agree with Imoore above. Once you already have moving water, you might as well aerate it! I recall some old threads on the forum discussing easy means of aerating in that situation.

Thanks guys! Would running the water down the 4" corrugated tubing help put oxygen in the water? I'm thinking as the water runs over the corrugation it would agitate it some?

Can't hurt. (I think it would help a fair bit? If you ever have an expert with a dissolved oxygen meter at your property, you could test a sample at each end.)

Plus zero frictional pressure loss in THAT pipe. It always helps your pump when you reduce the pressure it is pumping against.

Thanks, I'll try to use as much 4" as possible. I'll probably do something pretty simple for now, and if it really helps the pond, I'll do something better. One problem I have is eventually I'll have to trench it in under my road.