My beautiful daughter dug my pond in 1995 with the help of her brother disposing of the dirt. The pond is 3 1/2 ft deep & 12 ft long & 9 ft at the widest to 4 ft at other end.
The only thing I would have done differently is make the pond bigger. Some DIY pond builders make the mistake of not going deep enough. In NW Indiana we get some -10 degree days in January. I leave my Koi outside all year round by running my waterfall. I've had great success in finding info from many sources.