Do you know what the surface temp is where you tend to fish? I know that in Wolftever the surface temp has been in the upper 80's to low 90's during the day. I know that the Hiwassee starts out really cool, 50's but I would expect the surface temp near the TN river to be nearly that. Can you see the thermocline on your depth finder? If the surface temp is in the 80's I would doubt that the 'cline is deeper than 4-6 ft in the river, maybe it is but that would be strange. If it were that deep if you got into the water, you could feel the really cold water would be easily reachable with your feet. It hasn't been that shallow in Wolftever since May. I know 'cause I swim in the lake sometimes 3-6 times per week. You can learn a bunch by being in the water, feel the current, check the thermocline, feel the upwellings, it's interesting. The fish being shallow may be secondary to the upwellings near creek bends. In the most recent Bassmaster mag. I believe that it was Fritts or one of the other crankbait specialists that said that they think that people fish too deep in the summer and he targets areas that are in the 7-12 foot range(from what I remember). Unless there is grass to keep the dissolved oxygen level up in the area that hot water just won't have enough oxygen for the fish to be there.