An Update.

I have drained the pond. It took a while, given the monsoon type weather here in KY ovet the past month or so.

In one small area, I have found a hole aouut 3-4 inches in diameter that shows signs of water movement surrounding the hole.
The remainder of the pond bottom appears smooth silt, so I think I have found the source of my leak.

The hole is in the very bottom of the valley about 75 feet up from the dam, a couple of vertical feet up from the deepest part of the basin.

Any suggestions about the best way to seal a hole like this?
ONe thought was to dig it out and pour in gravel or concrete and then work a layer or clay over that area.

I am wondering about how big an area to build clay over??

Maybe I should still line the entire pond. Not sure.

Thx for any advice.

JOhn