East Branch Penobscot River At Grindstone flow report
As of July 16, 2026, East Branch Penobscot River At Grindstone is flowing at 628 cfs with a gage height of 4.89 ft, receding 18% over the past 24 hours. Source: USGS gauge #01029500, refreshed throughout the day.
Historical Data
East Branch Penobscot River At Grindstone at a glance
How East Branch Penobscot River At Grindstone is running right now, where it sits on the map, and the key gauge stats.
East Branch Penobscot River At Grindstone is flowing at 628 cfs, with the water sitting 4.89 ft at the gage. Flow is down 18% since yesterday as the gauge recedes.
This is USGS gauge #01029500 in Maine. Over the past 10 days the average has been 770 cfs, peaking at 845 cfs.
For real-time updates and historical context, see the realtime view or the historical comparison. Browse other gauges in the Maine flow report.
Engineering Data
Flow-duration statistics and observed peak-flow context computed from this gauge’s complete daily record (USGS #01029500).
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.
Streamflow Forecast
Over the next 5 days, East Branch Penobscot River At Grindstone is expected to hold near today's 628 cfs, toward roughly 642 cfs by 2026-07-20 (likely range 403-1024 cfs) -- running well below the seasonal normal.
Powered by PULSE — Snoflo’s forecast engine, trained on this gauge’s full record of storms, snowmelt, and dry spells.
| Date | Expected (p50) | Likely range (p25–p75) | vs normal | Projected stage |
|---|
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.
East Branch Penobscot River At Grindstone
The primary flow contributor is the East Branch Penobscot River, which receives water from several smaller tributaries. The area is home to several dams, including the Grindstone Project and the West Branch Project, which can affect water levels. The hydrology of the area is influenced by seasonal trends, with higher flows in the spring due to snowmelt and precipitation. The river is also known for its excellent trout fishing.
Nearby streamflow levels
Cross-check East Branch Penobscot River At Grindstone's discharge against nearby gauges to spot whether the change here is local or regional.
| Gauge | Streamflow |
|---|---|
| East Branch Penobscot River At Grindstone | 628 cfs |
| Mattawamkeag River Near Mattawamkeag | 351 cfs |
| Seboeis River Near Shin Pond | 47 cfs |
| Penobscot River At West Enfield | 5,350 cfs |
| Piscataquis River At Medford | 277 cfs |
| Meduxnekeag R Above S Br Medux. R Nr Houlton | 22 cfs |
Nearby snowpack data
Snowpack at SNOTEL stations near East Branch Penobscot River At Grindstone. 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 |
|---|---|
| Topsfield | 0 in |
| Dover-Foxcroft | 0 in |
Plan a trip
Reservoirs, boat launches, river runs, and fishing spots within driving distance of East Branch Penobscot River At Grindstone.
Boat launches
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River runs
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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 East Branch Penobscot River At Grindstone in the Snoflo app
Save this gauge as a favorite, set push alerts when streamflow crosses a threshold (e.g. "alert me when East Branch Penobscot River At Grindstone crosses 5,000 cfs"), and Snoflo's iOS app will push the moment USGS reports the crossing.
About East Branch Penobscot River At Grindstone
Where does the streamflow data for East Branch Penobscot River At Grindstone come from?
Discharge, gage height, and water temperature come directly from the USGS streamflow gauge 01029500. 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 East Branch Penobscot River At Grindstone 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 East Branch Penobscot River At Grindstone report
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