A good thing to know is that digging is easy, moving the dirt is the hard part. Digging a 1a pond with a D6 Cat or 650J Deere goes really quick. Getting rid of the huge piles of dirt are much more problematic.
A good way to kill 2 birds with 1 implement is to use a scraper, AKA earth mover. An 8 yard earth mover pulled by a large ag tractor can really dig AND move a lot of dirt in a 10 hour day. Even with a big scraper, distance is still a big obstacle, and you can still take lots more time transporting the dirt than digging it.
