Is the pond filling from the bottom up or can you see water running into the pond from somewhere?
Were you there to see the depth of the core? If so, did the builder dig into good clay before backfilling and compacting? Did the builder backfill the trench and center core with good clay?
Dave Sefton is near the area in Brownstown Illinois and an excellent pond builder. Here is a link to his Pond Boss info with his email address
Dave Sefton aka Mongo .
