I’m new to the forum but built exactly what your wanted my self a few years back.
2 words of advice that you do with what you like.
I’ve killed 2 3032 johndeeres. Great tractors but heavy work like that will destroy the hydro transmission ( I don’t think they make a Manuel) if they do I can’t speak of its quality.

You can rent a dozer for slightly more then a skidsteer and you will be way more productive.
I own a 333G skidsteer which is big as they come. After 12 hours I realized I needed a dozer.

As for the dam I used a track hoe and dozer.
My dam is 4’’ tall and core trench is 2’ deep.
My pond is 10’ deep.