BTW the old "wait for the hole to fill" technique is flawed. If I were to dig a hole today in the most horrible spot to dig a pond, it would fill up in about 5 seconds if I could even get the hole dug for all of the water in the way. Hell, I could white-water raft down my hillside this morning!

What you want to do is dig a few holes in the area the pond is to be dug to examine the soils. Are they clay all the way down? Great! Did you hit sand plus a water table? Ok! Expect level fluctuations more so than simply a clay-lined runoff pond. Hit nothing but sand and stone? Gonna have to bring in something to line the pond if you want it to hold water.

Last summer, I would have had to kick a Koala bear out of the way to find water in a hole. I would need to yank a hose in Australia back through the hole.(If I didn't fry up when trying to dig through the core of the earth).