There is a small private lake I fish often near my house, and a spring runs into it in two separate spots. It is supposed to be managed rather delicately by some pretty knowledgable folks I'd assume because the largemouth fishing is superb, but every claims that there is smallmouth in there, the deepest point in this lake might be 40 or 50' does this sound like a condition where a smallmouth could thrive and grow healthy or would these fish be long gone? Btw this is in Northern Tennessee.

Hey man, I dont think the bass will be that far down. Bass are restricted to how deep they can go because as water depth increases oxygen levels decrease so this limits where the bass can go.Another possible limitinf factor would be where the baitfish are going. Baitfish usually clump together in shallow coves and the bass more often then not will folow there forage.

Natural springs should keep the water cool. Sounds like a perfect environment for smallies IF someone actually ever put them in there in the first place.

The smallie will do perfectly in the cold water flows . More Oxygen & sinks down as it enters. The bait will like it also. Only the slower, warm water loving  largemouths may avoid it. That smallie is going to get HUGE.