This contractor has built many ponds in our area without problem. I didn't watch him pack the trench, but I have no reason to believe that he did not do it correctly. He seems to think that these tile were buried exceptionally deep and that the keyway went over top of them. Although I was helping when he brought the backhoe in the second time and dug in the front of the dam and found the second tile. It did not seem to be deep enough to be going under the keyway. Can this dam be repaired? Does his explanation that the bottom is not sealing and that the water we see in the middle back of the dam is being pushed down through the bottom and under the dam make any sense? I appreciate all of your ideas and comments......