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 CaliforniaRiver Group: Southern California
Monitor Stage: 10.85 FeetFlood Stage: 12.5 Feet

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

Historical Stage/Flow Data
Water Year
Peak Discharge (cfs)
Stage (feet)
Date
 Most Recent 5 Years
2025*
3,290
10.90
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
Official 7 Day National Weather Service Forecast   (CAZ043)
Today: Mostly cloudy This Morning and becoming partly cloudy. Patchy fog This Morning. Highs 71 to 75 near the coast to 77 to 81 inland. Areas of winds west to 10 mph.

Tonight: Partly cloudy. Patchy fog overnight. Lows 60 to 66. Areas of winds west to 10 mph in the evening becoming light.

Monday: Cloudy in the morning and becoming mostly sunny. Highs 72 to 76 near the coast to 78 to 83 inland. Areas of winds west to 10 mph.

Monday Night: Partly cloudy in the evening and becoming mostly cloudy overnight with patchy fog. Lows 61 to 67. Areas of winds west to 10 mph in the evening becoming light.

Tuesday: Cloudy in the morning and becoming partly cloudy. Patchy fog in the morning. Highs 73 to 77 near the coast to 80 to 85 inland. Areas of winds northwest to 10 mph becoming west in the afternoon.

Tuesday Night: Mostly clear in the evening and becoming partly cloudy overnight with patchy fog. Lows 63 to 68.

Wednesday: Partly cloudy with patchy fog in the morning and Becoming mostly sunny. Highs 77 to 82 near the coast to 85 to 90 inland.

Wednesday Night: Mostly clear in the evening and becoming partly cloudy. Lows 68 to 73.

Thursday: Partly cloudy. A slight chance of showers in the afternoon. Highs 76 to 81 near the coast to 84 to 88 inland.

Thursday Night: Partly cloudy. Lows 66 to 71.

Friday: Mostly cloudy in the morning, then partly cloudy with a slight chance of showers in the afternoon. Highs 74 to 79 near the coast to 81 to 85 inland.

Friday Night: Partly cloudy. A slight chance of showers in the evening. Lows 66 to 71.

Saturday: Mostly cloudy in the morning, then partly cloudy with a slight chance of showers in the afternoon. Highs 76 to 81 near the coast to 82 to 87 inland.
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.