I don't blame you for not wanting to put more of your hard earned money into it. I was blissfully unaware of pond construction when I hired my guy. I know for a fact all he used was a D6 to compact the clay, and I also never saw him dig a core trench either. The D6 was the only piece of equipment I saw him use. The first summer our pond dropped a good foot, or more, but it filled up in the fall. Since that first summer it never dropped more than 10" which it did last year. I did have our county soil guy come out before I dug my pond though. My neighbor had a backhoe and he dug some test holes for me. The county guy looked to see if we had enough clay, and run off which we had plenty of both. I was fortunate my pond guy new what he was doing. The other contractors I hired to build my house, I was not so fortunate.... at all! Best of luck, and sorry for your troubles.
