Some dirt movers may know a bit about pond building, coring and such, but all of them around here still insist on compacting with a dozer, say it's good enough, but it always results in leaky ponds unless they are excavated in pure clay. Don't buy the story that a dozer compacts. A heavy wheeled backhoe with a load of dirt in the bucket is far better than a dozer, but very time consuming on anything but a small job. The clay also needs to be compacted in lifts only about six inches thick.
