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

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.