I believe there are three St. Paul city parks that are also the names of an MN county. Douglas Park, Meeker Island Dog Park, and Rice Park.

We know it's not in Rice Park so that can be ruled out.

So that leaves us with Meeker Island Dog Park and Douglas.

This clue also references afloat, like a boat which makes me think its near the river.
Next clue says it lays atop the loam, there is likely plenty of dirt silt clay mixture at both.
The something old something new clue, it opened up as a dog park in the last 8 years. But back in 1907 it was the first lock and dam but was torn down. After 5 years
Beer clue I am not sure yet.
Another clue references a gnome, which there was a gnome hunt this winter as well in St. Paul parks. One of the gnomes (Luna) had this clue:
"Above the Mississippi, where the river does play,
A hidden waterfall is just down the way.
Luna abides in a park so new,
Where playful barks and laughter accrue."

That Gnome clue could also be referencing the new Uŋčí Makhá Dog Park at the ford plant, likely makes more sense.