Hydrology and Climate Data Sources
Happy Isles Gaging Station Webcam of the Merced River at the Happy Isles gaging station (provided by the USGS).
The Pohono and Happy Isles gages are located on the main stem of the river in Yosemite Valley. The Wawona gage is on the South Fork of the Merced, near the southern boundary of Yosemite National Park. The Briceburg gage is on Bureau of Land Management land, downstream of the park and downstream of the confluence with the South Fork Merced River.
The Grand Canyon of the Tuolumne gage is located just upstream of Hetch Hetchy Reservior, while a second gage is located just downstream of O'Shaughnessy Dam. Data are also available at Falls Creek, a tributary that flows into Hetch Hetchy from the north, and at Tuolumne Meadows, in the Yosemite high country.
Yosemite Hydrology Videos
These Yosemite-produced videos explore water-related topics:
Get Involved: Volunteer in the park's water quality monitoring effort of the Merced River. Help collect water samples that will be tested for nitrate and phosphorous concentrations. Participate 8 am to 5 pm the first Wednesday of every month (except December and February). Call the volunteer office at 209/379-1850 to sign up.