My interpretation of your question for the Smokies.
High elevation - anything over 3,000 ft. In the area of Chimney's trailhead and above qualifies.
Large river: East Prong of Little River (ironic), Abrams Creek, probably West Prong of the Little Pigeon
Medium river: Middle Prong of Little River
Small river: Road Prong, Thunderhead, West Prong of Little River, Laurel Creek, Anthony's Creek
My 2 cents.
His eye is on the sparrow and I know He watches me.