I would agree with the "make it deeper" idea.
If shallow, in addition to being riskier for injury, it will heat up and fill with weed and algae in summer. For farm ponds the recommended depth is usually pretty deep, over 2m, varying with location and intended use.
Perhaps if you have any kind of typical nosy local government concerns, it should be a "farm pond," since this is usually allowed and accepted, or some other kind of accepted thing.
Talk to a farmer, or make friends with an engineer I would say.
There is quite a science to building ponds and different types with different issues.
Probably the simplest is one that just collects rain or is filled by a small spring.
Plan to dam a creek or something like that though and the authorities will take some interest.
Sounds like a cool project.
I would be totally jealous!