Big River At Byrnesville flow report
As of July 13, 2026, Big River At Byrnesville is flowing at 1,200 cfs with a gage height of 5.47 ft, receding 57% over the past 24 hours. Source: USGS gauge #07018500, refreshed throughout the day.
Historical Data
Big River At Byrnesville at a glance
How Big River At Byrnesville is running right now, where it sits on the map, and the key gauge stats.
Big River At Byrnesville is flowing at 1,200 cfs, with the water sitting 5.47 ft at the gage. Flow is down 57% since yesterday as the gauge recedes.
This is USGS gauge #07018500 in Missouri. Over the past 10 days the average has been 601 cfs, peaking at 2,800 cfs.
Over the next 5 days, Big River At Byrnesville is expected to recede from today's 2800 cfs, toward roughly 1366 cfs by 2026-07-17 (likely range 554-3370 cfs) -- about normal for the date.
For real-time updates and historical context, see the realtime view or the historical comparison. Browse other gauges in the Missouri flow report.
Streamflow Forecast
Powered by PULSE — Snoflo’s Predictive Unified Learning & Simulation Engine, which learns from how this river has answered every past storm, snowmelt, and dry spell to forecast where it’s headed with a precision generic models can’t match.
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.
Big River At Byrnesville
The river is a tributary of the Meramec River and is fed by several smaller streams, including Flat River and Marble Creek. The primary flow provider for the Big River is rainfall, which fluctuates seasonally. During the spring and summer months, the flow is typically higher due to increased precipitation. There are no major dams on the river, and it is largely free-flowing. Streamflow data from the gauge can be used to monitor potential flooding and to inform management decisions related to water resources. One interesting fact about the Big River is that it was once a site of significant mining activity, which has left a legacy of contamination in some parts of the river basin.
Nearby streamflow levels
Cross-check Big River At Byrnesville's discharge against nearby gauges to spot whether the change here is local or regional.
| Gauge | Streamflow |
|---|---|
| Big River At Byrnesville | 1,200 cfs |
| Meramec River At Pacific | 31,300 cfs |
| Meramec River Near Eureka | 27,300 cfs |
| Williams Creek Near Peerless Park | 10 cfs |
| Kiefer Creek Near Ballwin | 5 cfs |
| Fishpot Creek At Valley Park | 1 cfs |
Nearby snowpack data
Snowpack at SNOTEL stations near Big River At Byrnesville. Spring snowmelt is the dominant driver of streamflow in mountain basins -- a deep snowpack upstream means more runoff later in the season.
| SNOTEL station | Snowpack |
|---|---|
| Festus | 0 in |
| Harvester | 0 in |
| Cottlevile 1s | 0 in |
| Dardenne Prairie | 0 in |
| Melvin Price Lock And Dam | 0 in |
| Cap Au Gris Lock & Dam 25 | 0 in |
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 Big River At Byrnesville in the Snoflo app
Save this gauge as a favorite, set push alerts when streamflow crosses a threshold (e.g. "alert me when Big River At Byrnesville crosses 5,000 cfs"), and Snoflo's iOS app will push the moment USGS reports the crossing.
About Big River At Byrnesville
Where does the streamflow data for Big River At Byrnesville come from?
Discharge, gage height, and water temperature come directly from the USGS streamflow gauge 07018500. 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 Big River At Byrnesville 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 Big River At Byrnesville report
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