This sounds like Copper Falls in northern Wisconsin (where the water is that reddish brown from the iron in it).
www.gowaterfalling.com/waterfalls/copper.shtml I suspect they may be part of the same larger geological system. It's been a LONG time since I visited the falls, but that part of the state and its forests always made me think of "This is the forest primeval." One could almost imagine an Ent or three among the trees and streams.
I live considerably farther south in Wisconsin, near the farms and rolling hills (and pastures and cheesemakers, of course
), which have made me think of the Shire since I first read LotR some... oh, 44 years ago. But no pictures, alas. Perhaps I should take a few en route to my birthday vacation this weekend.
