I didn't remember noticing it when I was there at Christmas, but I wasn't really looking either. I imagine if it's not there, it's likely that it will get there. It's in the Cumberland below Wolf Creek, and that river occasionally backfills somewhat into the Obey when the Cumberland's generating heavily and the Obey isn't.
On the other hand, generally speaking, there is a lot of algae and funk on the bottom downstream from the hatchery, presumably due to the hatchery effluent. It's possible that's what you saw.
It could be pretty heavy on the bottom in a lot of places on the Obey and you wouldn't know, since so much of the river is so deep. Some folks call the Caney "the Ditch" but that descriptor seems to fit the Obey a lot better to me.
bd
