Yosemite National Park is one of the most popular destinations in the world for active travelers, and many groups attempt to include a whitewater rafting trip along with their visit to the park. Both the Tuolumne River and the Merced River originate within the park on the highest peak in Yosemite, Mount Lyell. They are both easily accessible to Yosemite visitors since the meeting places for the respective rafting trips are along the major roads that lead into Yosemite National Park: Highway 120 and Highway 140.
The Mighty Merced River
The Merced River tumbles off the slopes of Mount Lyell down Nevada and Vernal Falls before meandering through Yosemite Valley. Rafting the flat water section of the Merced River through the valley is not permitted. After leaving the valley floor, the Merced River drops over a series of un runnable Class VI rapids before crossing the park boundary and entering a typical Sierra Nevada river canyon.
The whitewater stretch of the Merced begins just past El Portal and runs almost 30 miles to Lake McClure. Along they way are many fun Class III rapids as well as six classic Class IV rapids. Rafting trips on the Merced River can vary from Class II to Class IV depending on the section of river that you choose and the current flow of the river.
There are no dams above this section of river that impede the flow so the river flows naturally. This means that the water in the river comes from immediate rain and snow melt. During a typical California spring the Merced can be run from mid-April to mid-June. This changes each year depending on snow pack and weather. In bad water years the Merced will at least have dependable flows in May. In good years the Merced River has been known to flow through July.
The Mighty Tuolumne River
The Tuolumne River originates from the Lyell Glacier on the north side of Mount Lyell. It flows peacefully through Tuolumne Meadows before entering the steep Grand Canyon of the Tuolumne. After flowing through the Grand Canyon, the river is impounded by O’Shaugnessy Dam and Hetch Hetchy Reservoir. Below Hetch Hetchy, the river flows through a steep walled gorge before it’s confluence with Cherry Creek and the beginning of runnable whitewater.
The Cherry Creek run of the Main Tuolumne is for active people looking to push the envelopes of Class V paddling. This is definitely the most difficult section of commercially run whitewater in the United States and is among the most difficult in the world. This section of river is for people that have rafted several times before and enjoy rafting big drops and Class V.
Below the Cherry Creek run is the famous Main Tuolumne which begins at Merals Pool. This rafting trip is a two or three day adventure through a deep canyon full of fun Class IV rapids. This section of river is famous for its classic rapids and amazing side hikes up the free flowing Clavey River and the North Fork of the Tuolumne. This trip ends on Don Pedro Reservoir.
Since the Tuolumne River has dams that control the flow of the river, it can typically be run from April to early September. The best time to run the river is April through June when the water is big, the canyon is green, and the wildflowers are abundant. Once the snow melt ends, the water for the river comes from scheduled powerhouse releases. There is typically no water released on sundays, so plan your trip accordingly.
All commercial trips and most private trips meet at the La Casa Loma River Store on Highway 120 six miles east of Groveland. Only 52 commercial passengers in two groups are allowed each day so the river is never crowded. It is not uncommon to run the entire river for two days and not see another rafting group.