Does anybody know how I can determine if this rock shelf is actually the location of the leak?
I would think the rock is your problem, but sometimes there is also other pockets of material in the ground that could be causing your pond to drain water. Gravel, iron ore and sand are all good ways to drain water.
The water will drain down to the leak. Does it drain all the way down to the bottom? Or does it stop at a certain point? Where it stops, is where your leak ends.
Once you determine where the leak is, you can patch it with a few feet of compacted clay.
Eddie
