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 04 2026 at 1:26 PM PSTNext Issuance: Jan 05 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 chance of rain in the evening, then a slight chance of rain after midnight. Patchy fog early in the evening. Patchy fog after midnight. Lows 44 to 49. Southeast winds around 10 mph with gusts to around 20 mph.

Monday: Patchy fog in the morning. Mostly cloudy with a chance of rain. Highs 52 to 57. Southeast winds 10 to 15 mph with gusts to around 25 mph.

Monday Night: Mostly cloudy. A chance of rain in the evening, then a slight chance of rain after midnight. Lows around 44. Southeast winds 10 to 15 mph.

Tuesday: Mostly cloudy in the morning then becoming partly cloudy. Highs around 55. Southeast winds up to 10 mph in the morning becoming light.

Tuesday Night: Mostly cloudy. Lows 41 to 46. Light winds.

Wednesday: Mostly cloudy. Highs around 53.

Wednesday Night: Partly cloudy with a slight chance of rain. Lows around 40.

Thursday and Thursday Night: Mostly clear. Highs 48 to 54. Lows around 39.

Friday: Partly cloudy. Highs around 50.

Friday Night: Mostly clear. Lows around 38.

Saturday: Partly cloudy. Highs around 51.

Saturday Night: Mostly clear. Lows around 39.

Sunday: Partly cloudy. Highs 49 to 55.
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.