The Upper Putah Creek Watershed
encompasses 178,477 acres in southeast Lake County and some of Napa and Solano Counties. It is approximately 35 miles in length and 20 miles at its widest point. Elevations range from 440 feet at Lake Beryessa to 4722 feet at Cobb Mountain.
The two main sub-basins in the Upper Putah Creek Watershed are:
The Callayomi Valley (Middletown area) and Coyote Valley (Hidden Valley area).
The main drainage is into Lake Berryessa.
Tributaries include Putah Creek, Anderson Creek, St. Helena Creek , Dry Creek and Big Canyon creeks.