I am in Oklahoma and have a pond that just filled with all the rain. It too is seeping on the low backside of the dam. It was cored very deep with good clay. My dozer man who has built many many ponds for the state soil conservation department told me it is really not that uncommon to have some seepage and many times it will seal themselves as the dam cures and settles. The dam was packed pretty well and he indicated that even as hard as you try the dam ends up with a few root pieces and few small rocks that can allow some seepage. As time goes by he says those will rot, settle, clog, etc.

Curious if anyone has seen this to be the case.