Tuolumne River Watershed

The Tuolumne River begins its journey in the High Sierra of northern Yosemite National Park. The Tuolumne's two principal sources are Mount Dana and Mount Lyell, the tallest peak in Yosemite.

The Dana and Lyell tributaries meet at the eastern edge of Tuolumne Meadows and form the Tuolumne River as it flows through Tuolumne Meadows, the largest sub-alpine meadow in the Sierra Nevada.



From Tuolumne Meadows, the Tuolumne River drops nearly 4,000 feet on its western descent through the Grand Canyon of the Tuolumne. The river is impounded at Hetch Hetchy Reservoir. Numerous tributaries including Return, Paiute, Rancheria, and Falls creeks enter the Tuolumne River above O’Shaughnessy Dam.




At O'Shaughnessy Dam, about 33% of the river's flow is diverted through Canyon Tunnel and eventually to the San Francisco Bay Area, where it provides water for nearly 2.5 million people.



Below O'Shaughnessy Dam, the Tuolumne meanders through Poopenaut Valley before leaving Yosemite National Park and entering the Stanislaus National Forest. The Tuolumne River between Kirkwood Powerhouse and Don Pedro Reservoir is renowned as one of California's premier whitewater rivers, with class IV and V rapids spanning from the confluence of Cherry Creek and the Tuolumne River to Clavey Falls.

Middle Tuolumne River. The headwaters of the Middle Tuolumne River are between 7,000 and 8,000 feet in elevation inside Yosemite National Park. The Middle Tuolumne River joins the South Fork Tuolumne River outside of the park.

South Fork Tuolumne River. The headwaters of the South Fork Tuolumne begin between White Wolf and Yosemite Valley at elevations between 8,000 and 8,500 feet. The South Fork Tuolumne River exits the park just north of Hodgdon Meadow and upstream of its confluence with the main Tuolumne River.

Clavey River. The Clavey River begins in the high-country of the Emigrant Wilderness, with headwaters in Bell and Lily Creeks. The Clavey traverses 47-miles to its confluence with the Tuolumne River above Don Pedro Reservoir, and is one of three entirely free-flowing rivers left in the Western Sierra. Please see www.claveyriver.net for more information about this special tributary.