San Joaquin River Near Mendota Flow Report
As of July 21, 2026, San Joaquin River Near Mendota is flowing at 149 cfs with a gage height of 2.68 ft, receding 8% over the past 24 hours. Source: USGS gauge #11254000, refreshed throughout the day.
Historical Data
San Joaquin River Near Mendota at a glance
How San Joaquin River Near Mendota is running right now, where it sits on the map, and the key gauge stats.
San Joaquin River Near Mendota is flowing at 149 cfs, with the water sitting 2.68 ft at the gage. Flow is down 8% since yesterday as the gauge recedes.
This is USGS gauge #11254000 in California. Over the past 10 days the average has been 138 cfs, peaking at 163 cfs.
For real-time updates and historical context, see the realtime view or the historical comparison. Browse other gauges in the California flow report.
Engineering Data
Flow-duration statistics and observed peak-flow context computed from this gauge’s complete daily record (USGS #11254000).
Estimate flows at an ungauged site
Drainage-area ratio transfer from this gauge . Most reliable for hydrologically similar sites in the same watershed with area ratios between roughly 0.5 and 1.5.
Percentiles are flow-duration values computed from this gauge’s observed daily record as archived by Snoflo. Return periods are Weibull plotting-position estimates from observed annual maxima, provided as general reference context only. Always verify against official USGS NWIS records. Part of Snoflo for Engineering.
How does this compare to past years?
Year-over-year overlay, annual peak discharge, the full distribution of daily flows on record, and the gauge's rating curve.
Weather Forecast
Next 5 days, hour by hour
Temperature line with weather symbols on top, snow + rain accumulation as columns, humidity as a dotted line.
5-day forecast table
Every 3 hours, broken out across temperature, snow, rain, humidity, and wind.
| Time | Condition | Temp (°F) | Snow (in) | Rain (in) | Humidity (%) | Wind (mps) | Wind dir |
|---|---|---|---|---|---|---|---|
| Loading detailed forecast… | |||||||
15-day forecast
Daily temperatures, snow, and rain projected over the next two weeks.
San Joaquin River Near Mendota
The river's main tributaries include the Merced, Tuolumne, and Stanislaus Rivers. The river flow is affected by seasonal trends, with the highest flow typically occurring in the winter and spring due to snowmelt from the Sierra Nevada mountains. The river is also impacted by several dams, including the Friant Dam, which diverts water for irrigation and hydroelectric power generation. Interesting hydrological facts about the San Joaquin River include its historical significance as a major salmon spawning ground, and ongoing efforts to restore the river's ecosystem and fish populations.
Nearby streamflow levels
Cross-check San Joaquin River Near Mendota's discharge against nearby gauges to spot whether the change here is local or regional.
| Gauge | Streamflow |
|---|---|
| San Joaquin R Nr Mendota Ca | 149 cfs |
| Panoche C A I-5 Nr Silver Creek Ca | 0 cfs |
| Cantua C Nr Cantua Creek Ca | 0 cfs |
| Clear C Nr Idria Ca | 1 cfs |
| San Joaquin R Bl Friant Ca | 325 cfs |
| Salt Slough A Hwy 165 Nr Stevinson Ca | 44 cfs |
River levels & flood safety
- Read the level before you go
- A river that's runnable at one flow can be deadly at another. Check current discharge and gage height — like the values shown above — against the flood-stage thresholds, and remember levels can spike fast after rain or a dam release.
- Respect cold water
- Snowmelt rivers run cold even in summer. Sudden immersion triggers cold-water shock and saps strength within minutes. Wear a PFD, dress for the water temperature (not the air), and never wade or paddle alone.
- Watch for swiftwater hazards
- Strainers (downed trees), undercut rocks, and low-head dams are the deadliest features on moving water. High, fast, muddy water hides them. If in doubt, scout from shore and portage.
- Mind flash floods & releases
- Narrow canyons can flood from a storm miles upstream, and dam-controlled reaches can rise without warning. Know the forecast, the release schedule, and your exit before you launch.
Track San Joaquin River Near Mendota in the Snoflo app
Save this gauge as a favorite, set push alerts when streamflow crosses a threshold (e.g. "alert me when San Joaquin River Near Mendota crosses 5,000 cfs"), and Snoflo's iOS app will push the moment USGS reports the crossing.
About San Joaquin River Near Mendota
Where does the streamflow data for San Joaquin River Near Mendota come from?
Discharge, gage height, and water temperature come directly from the USGS streamflow gauge 11254000. Snoflo refreshes the time series throughout the day. Forecasts come from the NOAA / yr.no feed Snoflo's iOS app uses.
How often is the report updated?
USGS gauges report continuously (typically every 15 minutes). Snoflo pulls fresh values throughout the day — look for the "as of" timestamp on the streamflow hero card.
What's the difference between discharge and gage height?
Discharge (cubic feet per second, or cfs) is the volume of water flowing past the gauge each second. Gage height is how high the water sits at the gauge (feet). They're related by a rating curve specific to each gauge — higher water means more flow, but the exact ratio depends on channel shape.
How is "percent of median" calculated?
Today's discharge is compared to the historical median discharge on this calendar day across the gauge's full record. 100% = right on median; 200% = a very high year; 30% = a drought-level low.
What are flood stages, and is this river safe right now?
Flood stages are NWS-defined gage-height thresholds — Action, Minor, Moderate, Major — marking when nearby roads or floodplains start to be affected. "Safe" depends on your activity and skill: a level that's a fun paddle for an expert can be lethal for a wader. Always check the current level against the thresholds above and the safety links, and when in doubt, stay off the water.
Can I get alerts when San Joaquin River Near Mendota rises?
Yes — flow alerts are managed in the Snoflo iOS app. Favorite this gauge, set a streamflow threshold (e.g. "alert me when discharge crosses 5,000 cfs"), and you'll get a push the moment USGS reports the crossing.
Access the free San Joaquin River Near Mendota report
Create your free account to track this river — and everything else you love on the water.
- Flow alerts — get pinged the moment this river hits your range
- Save favorites — every river, lake & snowpack in one place
- Full history & forecasts — plus the free iPhone app