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

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MORMON SLOUGH - BELLOTA (MSGC1)
Latitude: 38.05º NLongitude: 121.01º WElevation: 130 Feet
Location: San Joaquin County in CaliforniaBulletin Group: San JoaquinRiver Group: North San Joaquin
Issuance Time: Jan 01 2026 at 1:19 PM PSTNext Issuance: Jan 02 2026 at 9:00 AM PST
Action/Monitor: 16.0 FeetMinor Flood: 22.0 FeetModerate Flood: 30.9 FeetMajor Flood: 31.9 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 Army Corps of Engineers.
View US Army Corps of Engineers 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* 904 6.89 Feb 15, 2025
2024* 1,100 7.44 Mar 3, 2024
2023* 11,400 21.80 Jan 16, 2023
2022* 1,950 9.21 Oct 25, 2021
2021* 839 6.78 Jan 28, 2021
 Historical High Stage/Flow Events (Period of Record - Dec 1997 to Present) - Ranked by Flow
2023* 11,400 21.80 Jan 16, 2023
1998* 9,395 18.48 Feb 3, 1998
2006* 9,328 18.40 Apr 4, 2006
2011* 8,354 17.22 Mar 24, 2011
 * Discharge affected by regulation or diversion
Location Photographs
ESRI™ Locator Map
Flood Impacts
31.9 FeetTop of Levee right bank levee. Water will overflow toward Bellota and Highway 26.
23.0 FeetDanger Stage
22.0 FeetFlood Stage
16.0 FeetMonitor Stage - Bike trail within lower Calaveras River channel flooded.
14.2 FeetUOP research within the Calaveras River channel is affected by water levels.
9.0 FeetWater rises out of the pilot channel but not yet on the levee slopes.
Official 7 Day National Weather Service Forecast   (CAZ019)
Tonight: Mostly cloudy. A slight chance of rain in the evening. Lows 45 to 50. Southeast winds 10 to 15 mph.

Friday: Mostly cloudy. Highs 54 to 61. Southeast winds 10 to 15 mph. Gusts up to 20 mph increasing to 30 mph in the afternoon.

Friday Night: Cloudy. A chance of rain in the evening, then rain after midnight. Breezy. Lows 50 to 55. Southeast winds 10 to 25 mph with gusts to around 45 mph.

Saturday: Rain in the morning, then rain showers and a slight chance of thunderstorms in the afternoon. Breezy. Highs 54 to 61. Southeast winds 15 to 25 mph with gusts to around 40 mph.

Saturday Night: Rain showers and a slight chance of thunderstorms. Lows 49 to 55. Southeast winds 10 to 20 mph with gusts to around 30 mph.

Sunday: Rain showers and a slight chance of thunderstorms. Highs around 54.

Sunday Night: Rain. Lows 45 to 50.

Monday: Rain likely. Highs around 51.

Monday Night: Mostly cloudy with a chance of rain. Lows 41 to 46.

Tuesday: Mostly cloudy with a slight chance of rain. Highs around 51.

Tuesday Night: Mostly cloudy. Lows around 42.

Wednesday: Mostly cloudy with a slight chance of rain. Highs around 50.

Wednesday Night: Mostly cloudy with a chance of rain. Lows around 41.

Thursday: Partly cloudy with a slight chance of rain. Highs 45 to 51.
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 Sacramento 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.