CNRFC - Hydrology - Observed River/Reservoir Conditions

SANTA MARGARITA RIVER - YSIDORA (YDRC1)

Latitude: 33.31º N	Longitude: 117.35º W	Elevation: 75 Feet
Location: San Diego County in California		River Group: Southern California

Monitor Stage: 10.85 Feet

Flood Stage: 12.5 Feet

Observed Data Credit
	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
Upstream Photo	Gage House Photo	Downstream Photo

ESRI™ Locator Map

Official 7 Day National Weather Service Forecast (CAZ043)

Tonight: Partly cloudy This Evening and becoming cloudy. Patchy dense fog. Lows 59 to 64. Light winds.

Saturday: Cloudy in the morning and becoming partly cloudy. Patchy dense fog in the morning. Highs 71 to 75 near the coast to 76 to 81 inland. Areas of winds south to 10 mph.

Saturday Night: Partly cloudy in the evening and becoming mostly cloudy. Patchy dense fog overnight. Lows 61 to 66. Light winds.

Sunday: Mostly cloudy in the morning and becoming partly cloudy. Highs 72 to 76 near the coast to 77 to 82 inland. Light winds becoming west 10 mph in the afternoon.

Sunday Night: Partly cloudy in the evening and becoming mostly cloudy. Lows 63 to 68. Light winds.

Monday: Mostly cloudy in the morning and becoming partly cloudy. Highs 74 to 77 near the coast to 79 to 84 inland.

Monday Night: Mostly clear in the evening and becoming partly cloudy. Lows 63 to 69.

Tuesday: Partly cloudy. Highs 74 to 78 near the coast to 80 to 85 inland.

Tuesday Night: Mostly clear in the evening and becoming partly cloudy. Lows 65 to 70.

Wednesday: Partly cloudy. Highs 77 to 81 near the coast to 84 to 89 inland.

Wednesday Night: Partly cloudy. Lows 67 to 72.

Thursday: Partly cloudy. A slight chance of showers in the afternoon. Highs 75 to 80 near the coast to 83 to 87 inland.

Thursday Night: Partly cloudy. A slight chance of showers in the evening. 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.

Flood Impacts
16.29 Feet	Major flood, 37,000 cfs. Widespread inundation of Camp Pendleton with evacuations likely. Flood of Record Jan 16, 1993.
13.78 Feet	Moderate 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 Feet	Minor flood stage, 8,000 cfs. Vandegrift Road has begun to flood downstream of the gage. Stuart Mesa Road closures can be expected.
10.85 Feet	2,500 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.

NWS RSS Feed