Making a natural puddle into a pond?

Part of our property has an aqufier on it. I assume that is why there is a huge puddle for about a month?
The last couple years its started attracting Ducks. Id love to dig the area deeper and wider in hopes of having a pond (i guess) the ducks and we could enjoy.
Is is possiable to simply dig down and out and it naturally fill up and be safe just like that?

Humans throughout history have "improved" springs. I did something like that, but it doesn't fill as high as I would like.  Careful digging though, I don't know much about your aquafer, but they can be soft mud who knows how deep.