I don't think you can safely say you won't need to top off the pond... In your area, you may well NEED to do so to keep from having a fish kill. I think a permanent tube/pipe underground is a good idea-you'll always have it if you need it.
If you have good clay at 12' you'll need to stock-pile that good clay and use on the sides as well as the bottom-build the entire tank out of it.
As for getting it out of the ground, the means would depend on finished pond size. if 3/4 ac or less, a solar pump would be sufficient but for a 1+ acre pond it's probably going to take a decent sized electric pump. At 1-1.75 acres your talking 6-10 acre feet of water=2 to 3 million gallons of water.

Last edited by Snipe; 07/14/20 07:48 PM.
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