Digging trenches can help dewater an area, but using a dozer may require slowly removing layers and letting things dry a bit. Even so, a dozer may get stuck, so having a way to pull it out is very helpful, either a winch or another machine. I dug my last pond this way with a small finish dozer and a backhoe, and am working on another pond. Been stuck twice but the tracks are very worn. Its not fun when you get stuck. An excavator is much better. That blue clay makes the build more difficult but also makes the pond seal up good.