I own a full size back hoe, a 100 hp tracked skid steer, and a full sized dump truck. My pond is 1/3 of an acre. Myself and an employee dug off and on it for over two years. We hauled of hundreds of dump truck loads of dirt and didn't even get it halfway dug. I hired a large excavator, a big dozer, and two belly dump trucks. The excavator never moved it just loaded trucks while the dozer fed it. Using the two belly dumps and my dump truck we completed the digging in 12 hours moving what I estimate to be close to 3,000 yards of dirt.

You have no idea how much dirt comes out of a hole until you start digging. I do a lot of dirt type work and it amazed me how much came out. The dirt fluffs up as you dig as it is compacted in the ground. The pile of dirt will be larger than the hole.

A backhoe has about a 1 yard loader bucket and a backhoe bucket that is about 1/4 yard. If your pond needs say 4,000 yards dug out that is 16,000 backhoe buckets. Where are you taking the dirt? It is no impossible but not very practical. It is the wrong tool for the job. With a backhoe you can only dig so much before you have to move which takes time.

I would hire it out to people with the right equipment. I spent about 5k hiring the trucks, dozer and excavator for mine. It would have taken me hundreds of hours and no telling how much diesel to do what they did in a day and a half.