Ponds are filled and/or fed with wells on good occasion. If you set the well pump up on a float switch, the pond will not overflow due to over-running the pump. If you want to create a cool water habitat, that's a different animal. A larger well and large pumps will be needed and you will have to have somewhere for the overflow to go besides your neighbors yard, lol.

Wells can certainly be finicky and dry up on you or not supply enough flow for your liking.

The fisheries that I have been to used wells OR had natural high flow springs feeding a long series of ponds. Lots and lots of water. One of the springs produces up to 1000 gallons a minute. They have 200 ponds that make up 400 surface acres. Pretty cool to see!

Fish on!,
Noel