I just spent a bundle on a 1/2 acre pond 14' deep and now the dam is leaking. I think I know where the leak is as it was leaking in this place when the water was only 2' high. The contractor told me the leak was ground water,but I had a hunch it was coming from under the earth dam. I do not think he dug the keyway out properly. Water is coming out about as fast as a house spigot turned on 1/2 way going through a garden hose. The contractor also told me it would seal it self after the oozing clay reached that end of the pond,but I am not holding my breath.
If I drain the pond down to 2' deep and dump some bags of bentonite clay in the area I suspect is leaking do you think that will seal it ?