Found in a park near the river in Charles City, IA. The plaque isn't at all helpful as it just has someone's name on it.

Posted Aug 7, 2018, 8:32 PM UTC
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Posted Aug 7, 2018, 8:32 PM UTC
My guess is the person named on the plaque worked for or helped establish the local water company, or perhaps local water infrastructure like a set of locks. The valve wheel and housing look like water stuff to me. The rock is an attempt to make it art.
That's an interesting thought for sure. There is a small damn on this section of the river not far downstream but it's not large enough to contain a lock system or even gates to control the flow; it's the type that's just meant for flood control essentially. Still, I'm wondering if this could be part of an old water mill for making flour; although the stone doesn't appear to be shaped in a way that would work in one?
If it has a plaque with a name on it, it is probably art. Have you tried googling the name to see if any (local) artists turn up in the search?
It was a memorial plaque...in memory of some local guy that my wife recognized being from the area, like his family donated it to the park.
Being important enough for a plaque usually means having a newspaper article about the plaque placing. If the plaque and the artwork are related it will surely be mentioned in the article.
Does your local or regional newspaper have a searchable online archive?
That's a good thought but I was just visiting the area and this stone thing intrigued me as I can usually figure these types of things out!