I had a one acre pond built 2 years ago. It has leaked since it was constructed and never filled up. During the first winter it filled to 4 feet and then we noticed water leaking under the center of the dam. The contractor discovered that he had left a field drainage tile under the dam. He patched and compacted the dam on the back side. Last winter- same thing. We would get 3 or 4 feet in the pond and it would all drain out over the next 2 or 3 weeks. After it completely drained this summer, he opened up the center front with a backhoe and discovered two clay tiles both full of water. These were dissected and the hole in the front of the dam was mechanically packed (we added some bentonite to the repaired area). I was optomistic and the latest storms here filled the pond up to within 3 feet of the drain. It is designed to be 10 feet deep at the dam. Today the ground is frozen and frosty here. and it is easy to see that there is still water leaking at the base of the center of the dam. I am a patient man, but at this point, I am losing confidence in my builder and think that he may have built us a faulty dam. He is suggesting that the pond bottom may be leaking due to the increased pressure of the water and that water is being forced under the keyway and up at the base of the dam in the center. We have had record rains here during the first two weeks of January and the ground is saturated. His explanation does not appear to hold water to me. Pun intended! I may be at a point where I need an expert on my side to find out what is going on and who should be responsible for fixing it....Any suggestions?