National Weather Service California Nevada River Forecast Center Department of Commerce National Oceanic and Atmospheric Administration National Weather Service

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SANTA MARGARITA RIVER - YSIDORA (YDRC1)
Latitude: 33.31º NLongitude: 117.35º WElevation: 75 Feet
Location: San Diego County in CaliforniaBulletin Group: Southern CaliforniaRiver Group: San Diego/Inland
Issuance Time: Jan 29 2026 at 1:02 PM PSTNext Issuance: Jan 30 2026 at 9:00 AM PST
Action/Monitor: 10.85 FeetMinor Flood: 12.5 FeetModerate Flood: 13.78 FeetMajor Flood: 16.29 Feet

Please Note:
1) Each individual timeseries plotted on the graphical river forecast can be toggled on and off by clicking the legend entry above. If the "Observed (Raw Data)" contains bad data and is toggled off, the plot will scale to the remaining timeseries.

2) At extremely low river flows, the "Observed (Raw Data)" may show readings below the lower end of the available rating table, while the "Observed (Simulated)" will only show values at the bottom of the rating table, creating a potential discrepancy between the two readings.
Observed Data Credit
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Raw streamflow data is provided by the US Geological Survey (USGS).
View US Geological Survey (USGS) Data for this station location.

Verification - Historical Graphical RVF
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To view other verification locations, use our Historical Graphical River Forecast Interface.
Historical Stage/Flow Data
Note: Water Year 2025 is currently showing peak daily mean values. These will be updated to instantaneous peaks in the coming months.
Water Year
Peak Discharge (cfs)
Stage (feet)
Date
 Most Recent 5 Years
2025*
708
9.10
Feb 14, 2025
2024*
8,250
11.26
Mar 31, 2024
2023*
11,100
11.73
Jan 16, 2023
2022*
4,270
9.37
Dec 24, 2021
2021*
1,120
7.31
Dec 29, 2020
 Historical High Stage/Flow Events (Period of Record - Sep 2001 to Present)** - Ranked by Flow
1993*
44,000***
20.47***
Jan 16, 1993
1927
33,600****
18.00
Feb 16, 1927
2017*
31,200
14.60
Jan 22, 2017
1938
31,000
12.70
Mar 3, 1938
2011* 30,000*** 12.29 Dec 22, 2010
2019*
29,500
15.07
Feb 14, 2019
* Discharge affected by regulation or diversion
** Most recent continuous record back to Sep 2001 with segmented periods back to Feb 1923
*** Estimated value
**** Highest flow since regulation by Skinner Reservoir began in 1974
Location Photographs
ESRI™ Locator Map
Flood Impacts
16.29 FeetMajor flood, 37,000 cfs. Widespread inundation of Camp Pendleton with evacuations likely. Flood of Record Jan 16, 1993.
13.78 FeetModerate flood stage, 17,000 cfs. Vandegrift Road is flooded for several miles downstream of the gage site. Stuart Mesa Road is flooded near the bridge.
12.5 FeetMinor flood stage, 8,000 cfs. Vandegrift Road has begun to flood downstream of the gage. Stuart Mesa Road closures can be expected.
10.85 Feet2,500 cfs. The river has reached monitor stage. Personnel begin regular patrols along the levee.
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 Diego 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.