As he pushes dirt out of the pit and shapes the pond, the final product will have a clay liner. That clay liner should be compacted, all the way around the pond, top to bottom. It should be part of the process of building and molding the pond. I know the area where you are excavating, and there is good clay. But, there are also fractures of sand and gravel in different places. Be aware of those. Anywhere clay is placed, it should be compacted, just as a matter of the business of building the pond. I know you have had a hard time finding a contractor, so I would simply communicate to him what you expect, and then hold him to it. Even though a bulldozer isn't the best tool for compaction, it will be adequate for the heavy clay soils you have near Pilot Point.
