What can I use to dig a pond if I can't do it by hand? I was thinking of renting something to use. I would like it to be 3 ft deep an about 20 ft long and 12 wide. We have alot of old tree roots (trees are gone now) and the area is kind of rocky so digging by hand is a last resort. any ideas? I was thinking I could make it raised for a foot, and that would make 2 ft my deepest area for digging. I wasn't sure how that would work in the winter though for the fish. I will probably only have goldfish because the pond will not be big enough for koi.