TidalMapPotomac River near Wash, Dc Little Falls Pump Sta Water Level Today
NWS river forecast
| When | Stage | Flow |
|---|
Forecast from the NOAA National Water Prediction Service. Issued a few times a day and only while a forecast is active. Not for navigation.
Last 30 days
About this gauge
USGS gauge 01646500 sits on the Potomac River and reads everything draining 11,560 square miles of the Middle Potomac-Catoctin basin. Its datum sits 37 feet above sea level NAVD88. Daily flow has been on record here since 1930, 96 years of it.
Where this gauge sits in the drainage
Three gauged sites sit upstream of here. The closest is Potomac River at Edwards Ferry near Poolesville,md, reading 11,130 square miles. This gauge adds the 430 square miles that drain in between.
Normal flows here
The Potomac River runs a median of 6,325 cfs at this gauge across 96 years of record. March is the fullest month at a median 15,700 cfs, and September the leanest at 2,295 cfs. The highest daily mean on record is 426,000 cfs in 1936, and the lowest is 121 cfs in 1966.
| Month | Median flow | Share of annual median |
|---|---|---|
| Jan | 9,260 cfs | 146% |
| Feb | 11,900 cfs | 188% |
| Mar | 15,700 cfs | 248% |
| Apr | 14,300 cfs | 226% |
| May | 11,200 cfs | 177% |
| Jun | 5,880 cfs | 93% |
| Jul | 3,610 cfs | 57% |
| Aug | 2,810 cfs | 44% |
| Sep | 2,295 cfs | 36% |
| Oct | 2,510 cfs | 40% |
| Nov | 3,645 cfs | 58% |
| Dec | 7,390 cfs | 117% |
Medians from the USGS daily-statistics record, 1930 to 2026. A month at 100% is running at its own long-term median.
Flood stages and record crests
The Potomac River reaches flood stage at this gauge at 10 feet. NWS starts watching it at 5 feet. The highest crest on record is 28.1 feet, in March 1936.
| Category | Gage height |
|---|---|
| Action | 5 ft |
| Minor flooding | 10 ft |
| Moderate flooding | 12 ft |
| Major flooding | 14 ft |
| When | Crest |
|---|---|
| March 1936 | 28.1 ft |
| October 1942 | 26.9 ft |
| April 1937 | 23.3 ft |
| June 1972 | 22 ft |
| January 1996 | 19.3 ft |
Flood categories and crest history from the NOAA National Water Prediction Service, gauge BRKM2. Stages are gage height, not depth. Not for navigation.
Nearby river gauges
- Dead Run at Whann Avenue near Mclean, VA
- Four Mile Run at Hwy 29 at Falls Church, VA
- Tripps Run at Falls Church, VA
- Fourmile Run at Alexandria, VA
- Difficult Run near Great Falls, VA
- Turkey Branch near Rockville, MD
- Sligo Creek near Takoma Park, MD
- Cameron Run at Alexandria, VA
- Northwest Branch Anacostia River near Colesville, MD
- Accotink Creek near Annandale, VA
- Northwest Branch Anacostia River at Brentwood, MD
- Long Branch near Annandale, VA
Live streamflow and gage height: USGS gauge 01646500. Percentile context computed against the gauge's period of record. Not for navigation.
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