When I saw the pond around here dug they hit no water during the construction and no wet areas ever showed in the pond. It was right after the construction we received two rains of an inch each in a weeks time. When the rain finished you could see ripples on the pond surface from water filling from below. The pond continued to fill and rose around 4 feet before it leveled off. Then no rain for appx 6 weeks and pond dropped probably 3 feet, my guess would be through this same hole, could be wrong. I just wondered if any of those ideas would be useful to keep letting the water in after a rain but stop it from going out once it leveled off. Can a pond bottom be compacted enough to keep this from occurring in the first place?