posted 10 years ago
If you're going to have an unexpected pond you want it deeper, so I would dig deeper. If the layer holds, then you've got an unexpected pond -- a resource you didn't expect and weren't planning for, but plans can be amended to reflect fortuitous discoveries, right? (I was just today talking with a guy who found an unexpected pecan tree in an area he was planning to bulldoze -- so he changed his plan.)
If the layer doesn't hold, you've got a deeper krater than you were wanting (which might be useful anyway) and all you're out is some labor and fuel and machine wear-and-tear.
We've actually got an unexpected micro-pond left behind by the local water utility. They were doing some digging trying to find an old abandoned water line on a utility easement across this property, and they failed to fill back in one hole that was about six feet deep and eight feet across. It promptly filled with water, which to my surprise didn't diminish much even during several long drought-filled summers. I don't know much about the soils in that location or the water table, so I'm not entirely sure what's going on with it.
At first we considered the new pond a hazard and kept hounding the utility to come back and fill it in. They made a lot of promises, but never showed up. Meanwhile, the dangerous steep sides (I was afraid of losing dogs in there) crumbled to a more safe and stable angle; vegetation came up, and I realized the pond was in reach of the feeder roots of one of our pecan trees, so now I'm content to have it stay.