Thanks for all of your comments. Dave's question about tile causes me to add a little more information that I didn't include in my original posting. After the spring thaw, the pond filled with about 3 feet of water. I was ready to order my fish! It all drained out in about two weeks and I discovered that the contractor had left a drain tile (we built the tile in a ravine in an old corn field) which apparently went all the way under the dam keyway! Water was running through the drain and under the dam. He excavated in front of the dam and behind it and packed the soil in mechanically on both sides. He left the backside open so that we could be sure that there was no leakage through or around the old tile. It appears to me that this leak was repaired, although I am concerned with the longterm affect of this type of repair -like that is my only problem! I just wanted to add this to the mix for your comments............