I fly fished a stretch of Timber Coulee in the Driftless which had a cliff along the far shore. One spot featured this spring emerging from the cliff. You can see the water dripping into the stream in the photo below.
This is not a really deep run but the trout like the deep cover. Some really good trout were rising right back into the brush.
The concentric circles are rising trout during a baetis emergence in a big pool in Timber Coulee (in the Driftless).