We do this all the time here on the prairie. 1,000s and 1,000s of acres actually.
As said above, it's easier to build a levee around it.
I did this for my landowner where I farm at.
Planted strips of millet in it, and it was beautiful.
Sadly it was never pumped with water...we had to run a half mile of pipe and 2 pumps from one reservoir to this spot.
We just couldn't ever find time to do it.
Finally got it done, and season is almost over.
I will make the levees a little wider for next go round, but they work like this.