The geology is fairly well understood. In building the pond we moved between 13 to 15K cubic yards of dirt. In all of the dirt only 2 small rocks where found. I don't know how far down it is to bedrock but I don't think that is the issue. I leaning more towards it being a sand vain that is sucking the water away. We did hit 2 small pockets of sand while building the pond. We where able to completely dig them out and fill with clay. In total they where about 10 yards of sand and it was reomved from the pond area. Both of them where at the bottom of the ravine in the basin of the pond and the reason why I don't have the 25+ deep hole in the pond that I wanted. One of those areas is under about 8' of clay and the other in under at least 3' of clay.
