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: Jul 01 2025 at 7:40 AM PDTNext Issuance: Jul 02 2025 at 9:00 AM PDT
Action/Monitor: 8.2 FeetMinor Flood: 11.2 FeetModerate Flood: 13.3 FeetMajor Flood: 16.0 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
Water Year
Peak Discharge (cfs)
Stage (feet)
Date
 Most Recent 5 Years
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
2020*
6,680
10.78
Apr 10, 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
2019*
29,500
15.07
Feb 14, 2019
2005* 25,600*** 13.5*** Jan 11, 2005
1980* 24,000*** 18.80 Feb 18, 1980
* 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
16.0 FeetMajor flood, 37,000 cfs. Widespread inundation of Camp Pendleton with evacuations likely. Flood of Record Jan 16, 1993.
13.33 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.
11.16 FeetMinor flood stage, 8,000 cfs. Vandegrift Road has begun to flood downstream of the gage. Stuart Mesa Road closures can be expected.
8.18 Feet2,500 cfs. The river has reached monitor stage. Personnel begin regular patrols along the levee.
Official 7 Day National Weather Service Forecast   (CAZ043)
Tonight: Partly cloudy this evening and becoming mostly cloudy. Patchy fog overnight. Lows 56 to 62. Areas of winds west 10 mph this evening becoming light.

Wednesday: Mostly cloudy in the morning and becoming partly cloudy. Highs 70 to 74 near the coast to 76 inland. Areas of winds west to 10 mph.

Wednesday Night: Partly cloudy in the evening and becoming mostly cloudy overnight with patchy fog. Lows 56 to 62. Areas of winds west 10 mph in the evening becoming light.

Thursday: Mostly cloudy with patchy fog in the morning and Becoming partly cloudy. Highs 69 to 73 near the coast to 75 inland. Areas of winds west to 10 mph.

Thursday Night: Partly cloudy. Patchy fog overnight. Lows 57 to 62. Areas of winds southwest 10 mph in the evening becoming light.

Independence Day: Patchy fog in the morning. Partly cloudy. Highs 71 to 75 near the coast to 76 to 79 inland.

Friday Night: Mostly clear in the evening and becoming mostly cloudy overnight with patchy fog. Lows 57 to 62.

Saturday: Mostly cloudy with patchy fog in the morning and Becoming mostly sunny. Highs 73 to 76 near the coast to 80 inland.

Saturday Night: Mostly clear in the evening and becoming mostly cloudy overnight with patchy fog. Lows 58 to 63.

Sunday: Cloudy with patchy fog in the morning and becoming mostly sunny. Highs 73 to 76 near the coast to 80 inland.

Sunday Night: Mostly clear in the evening and becoming mostly cloudy overnight with patchy fog. Lows 59 to 63.

Monday: Cloudy with patchy fog in the morning and becoming mostly sunny. Highs 73 to 77 near the coast to 80 inland.

Monday Night: Partly cloudy in the evening and becoming cloudy overnight with patchy fog. Lows 59 to 64.

Tuesday: Cloudy in the morning and becoming partly cloudy. Patchy fog in the morning. Highs 74 to 78 near the coast to 80 to 83 inland.
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.