My parents antebellum home (Huntsville, AL) has a filled cistern in the side yard. I am interested in digging it out. I can see the circle outline- perhaps 12 foot across with the wall appeargin to be about 12" thick. House built ca 1812.

Any idea of expected depth? I would love to turn it into a mini-swimming pool or even a ****fish pond or fountain.

Has anyone ever converted an old cistern into a pool of any kind?

I have heard reports of people digging up old cisterns and finding them very snakey (dad did as a child) but we are in a downtown area, which does have caves, but we are not near a river--mayeb a mile or so from a large spring but I doubt this would be connected.

The dirt has settled repeatedly through the years (we've had property for 50 years) and filled it with countless wheelbarrows of dirt and even considerable logs down into a hole that repeatedly opened. We do not think we are directly over a cave but they are near by. Neighbors have had not problems digging new pools. The amoutn of fill we have added over the years makes me wonder if it is closed, very deep, or what. Dad was always against digging it out due to his snaky experience as a child climbing into an old cistern near the TN river- filled with water moccasins.

Thoughts?