Maybe this was already posted, but when the contractor built the dam did he strip off all organic material and dig a core trench under the dam to assure the right type of clay was present?If not, that could be a problem. Check the ground behind the dam and make sure it is not wet. As long as they built the dam in lifts of 1 to 2 ft, compaction shouldn't be a problem (even with track machines).If they threw a pile up with the hoe and leveled it a little with dozer then that's a problem. Bentonite is not the answer in my opinion..Even if you did try it, you would have to drain the pond and incorporate it in the soil. Good luck
