Thanks for the additional responses. It is now muddy / slick enough that I can't do much more to it and the potential "spring" areas are now under several feet of water. I am planning on draining as much as possible (down to the ten foot level probably) from the pond next spring or early summer to do some additional work on the lake. I can look at digging the topsoil out more and packing clay at that time or possibly might be able to determine that it isn't leaking. Frankly, at this point, I'm hoping for the latter. I don't know how long the soil will take to dry out enough to do much after being underwater for a few months.

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