From WoWWiki

Wellspring River comes from a natural spring that lies deep within the great tree Teldrassil. The river flows north from Wellspring Lake and cascades over the edge of Teldrassil in a great waterfall to the sea, far below. Crazed timberlings now patrol the banks of the river, attacking anyone who wanders near.

Subzones of Teldrassil
Aldrassil • Ban'ethil Barrow Den • Ban'ethil Hollow • The Cleft • Darnassus • Dolanaar • Fel Rock • Gnarlpine Hold • Lake Al'Ameth • The Oracle Glade • Pools of Arlithrien • Rut'theran Village • Shadowglen • Shadowthread Cave • Starbreeze Village • The Veiled Sea • Wellspring Lake • Wellspring River