CNRFC - Hydrology - Observed River/Reservoir Conditions

MERCED RIVER - YOSEMITE NP AT HAPPY ISLES (HPIC1)

Latitude: 37.73º N	Longitude: 119.56º W	Elevation: 4017 Feet
Location: Mariposa County in California		Bulletin Group: San Joaquin		River Group: San Joaquin

Action/Monitor: N/A

Minor Flood: 7.5 Feet

Moderate Flood: 10.0 Feet

Major Flood: 13.27 Feet

Plot Type:

Observed Data Credit
	Raw streamflow data is provided by the US Geological Survey (USGS). View US Geological Survey (USGS) Data for this station location.

Historical Stage/Flow Data
Water Year	Peak Discharge (cfs)	Stage (feet)	Date
Most Recent 5 Years
2025	2,400	6.22	May 11, 2025
2024	2,980	6.80	May 19, 2024
2023	4,980	8.42	May 23, 2023
2022	2,430	6.25	Oct 25, 2021
2021	1,410	5.02	May 7, 2021
Historical High Stage/Flow Events (Period of Record - Aug 1915 to Present) - Ranked by Flow
1997	10,100	13.27	Jan 2, 1997
1956	9,840	12.73	Dec 23, 1955
1951	9,260	11.55	Nov 18, 1950
1965	9,240	11.50	Dec 23, 1964
1938	8,400	10.40	Dec 11, 1937
2018	8,060	10.09	Dec 07, 2018

Location Photographs
Upstream Photo	Gage House Photo	Downstream Photo

ESRI™ Locator Map

Flood Impacts
13.27 Feet	Flood of Record: 1/2/97. $178 million in damage to Yosemite Valley.
10.0 Feet	Northside Drive at Wosky Pond, Southside Drive at Chapel Meadow, El Capitan crossover, and Sentinel crossover are impassable to vehicles.
8.2 Feet	Swinging Bridge overtops. Water on road at Northside Drive, Southsie Drive, El Capitan crossover, and Sentinel crossover.
7.5 Feet	Flood Stage. Housekeeping camp and Yosemite Valley backpacker campground begin to flood.
7.0 Feet	North Pines and Lower Pines campgrounds begin flooding.

Product Disclaimer

This river graphic is not intended to serve as a substitute for official flood watches, warnings, advisories, or statements issued by the NWS San Joaquin Valley-Hanford Weather Forecast Office. Observations are preliminary and subject to change. River levels identified as "forecast" should be consistent with those contained in official NWS products. River levels identified as "guidance" have significant uncertainty due to future weather or reservoir regulation and are provided for planning purposes only.

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