There’s definitely some temperature anomalies that take place in coal country creeks from the effect of the mine and treatment facility discharges. The net result is an effect similar to limestone influenced streams, speaking strictly temperature wise. Not like the Letort, but say more like a stream like Spring or BFC. They can be a few degrees warmer in Winter, and stay cool in the Summer. Cooler than you’d expect for their size. One of my Winter haunts too.
Those Browns definitely look like some “acid tolerant” ones from the stream bottom. Very nice.