The Merced River is a tributary of the San Joaquin River and flows for 112 miles from its headwaters in Yosemite Valley. The Merced has a watershed of 1,726 square miles.
The South Fork of the Merced and the Main Fork (through Yosemite Valley) have been designated Wild and Scenic Waterways to help preserve this natural resource.
Although the river has been preserved in the upper reaches, it is still used for irrigation in the lower watershed.
Barriers, constructed to harness the river, have prevented historic runs of salmon into Yosemite Valley. The Merced is one of the southern-most salmon spawning rivers in America.