Eel River Watershed
Maps of Mendocino County's Water Supply & the Potter Valley Project
Map of the Eel River Watershed
The Eel River Watershed covers over 3,500 square miles. The Counties of Humboldt, Trinity, Tehama, Glenn, Colusa, Lake and Mendocino share this diverse river system. The main tributaries of the Eel River include the Middle Fork, North Fork, Van Duzen, South Fork and the Upper Mainstem. The Potter Valley Project is located in the very highest reach of the Upper Mainstem of the Eel River.