Potomac River at Washington
District of Columbia · Paddling & whitewater
Measured at USGS 01646500 — POTOMAC RIVER NEAR WASH, DC LITTLE FALLS PUMP STA · NWS forecast point BRKM2
Reading taken Jul 28, 11:50 PM UTC
In its normal runnable range
At 3,400 CFS, this gauge is running 103% of normal for late July — close to the 3,310 CFS median USGS has recorded for this date across 96 years of record (1930–2026). The stage is 1.9 ft below the NWS action stage of 5.0 ft.
Data-derived guidance from USGS and NWS published values — not official advice, and not a safety assessment.
Sponsor Potomac River
Put your outfitter, guide service, cabin rental or shuttle in front of everyone checking this stretch before they drive out. One exclusive sponsor per river.
Cancel anytime · Questions?
Flood stages at Washington
Official National Weather Service categories for gauge BRKM2, issued by WFO LWX. Impact statements are the NWS's own wording for this location, reproduced verbatim.
-
Major flood 14.0 ft
- 14.0 ft Significant portions of the C&O Canal towpath are flooded. The Blockhouse Point Park is flooded. Water reaches the retaining wall at Overlook 1 at Great Falls National Park but does not overtop it.
- 15.0 ft Most of the C&O Canal towpath from Pennyfield downstream is flooded.
- 16.0 ft Water reaches the clubhouse on Sycamore Island.
- 17.0 ft Water overflows the overlooks at Great Falls National Park and approaches the lower level of the visitors center. Most of the C&O Canal towpath downstream of Pennyfield is flooded. There is approximately a foot of water in the clubhouse on Sycamore Island.
-
Moderate flood 12.0 ft
- 12.0 ft The C&O Canal overflows at the Great Falls Tavern. Water covers the towpath in many areas.
-
Minor flood 10.0 ft
- 10.0 ft Water begins to overflow the banks into low lying areas on the Maryland side of the river near Little Falls. Water begins to enter the canoe shed at Sycamore Island.
- 11.0 ft Water covers the towpath between Swains Lock and Pennyfield Lock, mileposts 17 to 19 on the C&O Canal.
- 11.5 ft Water covers the towpath in multiple spots between the Washington Aqueduct Dam and Pennyfield Lock, mileposts 15 to 19 on the C&O Canal.
-
Action 5.0 ft · 22,000 CFS
- 5.0 ft Portions of the Potomac Heritage Trail begin to flood. Water begins to affect portions of the Billy Goat Trail between Great Falls and Carderock. These trails will be closed.
- 5.5 ft Water reaches the top of the ferry landing for Sycamore Island. Ferry service to the island will likely be suspended.
- 7.0 ft Upper portions of the River Trail at Great Falls National Park begin to flood and will be closed.
- 9.0 ft Several trails on both sides of the river between Great Falls and the Chain Bridge are flooded and will be closed.
- Right now 3.10 ft
NWS forecast: 2.90 ft by Jul 29, 6:00 AM UTC.
12 months of flow at Washington
Daily values from USGS gauge 01646500. Provisional data, subject to revision.
Highest crests on record at Washington
| Stage | Flow | Date |
|---|---|---|
| 28.10 ft | 484,000 CFS | Mar 19, 1936 |
| 26.88 ft | 447,000 CFS | Oct 17, 1942 |
| 23.30 ft | 347,000 CFS | Apr 28, 1937 |
| 22.03 ft | 359,000 CFS | Jun 24, 1972 |
| 19.29 ft | 347,000 CFS | Jan 21, 1996 |
| 17.99 ft | 317,000 CFS | Nov 7, 1985 |
| 17.84 ft | 314,000 CFS | Sep 8, 1996 |
| 17.60 ft | 216,000 CFS | Aug 20, 1955 |
| 15.62 ft | 181,000 CFS | Oct 30, 1937 |
| 15.25 ft | 168,000 CFS | May 14, 1932 |
Historical crests published by the National Weather Service for this gauge.
About Potomac River at Washington
This gauge measures Potomac River at Washington, District of Columbia — the reading paddlers, anglers and outfitters on this stretch check before committing to a shuttle.
Little Falls; the DC-region reference gauge.
Raw CFS means little on its own, so every reading on this page is shown against the USGS median for the same calendar day — 3,310 CFS for late July, from 96 years of record.
Because the National Weather Service also operates a forecast point here, the page carries the official flood-category ladder and the NWS's own stage-by-stage impact statements.
Potomac River at Washington — common questions
What is the current flow on Potomac River at Washington?
As of the last reading on this page, Potomac River at Washington was running 3,400 CFS at a gage height of 3.10 ft, or 103% of the USGS median for this date. The number updates automatically from USGS gauge 01646500, which reports every 15 to 60 minutes.
Is that high or low for this time of year?
The USGS median flow for late July at this gauge is 3,310 CFS, calculated from 96 years of record (1930–2026). Comparing today's reading against that median is the only way a raw CFS number tells you anything — 200 CFS is a drought on one river and a flood on another.
How often does this reading update?
USGS transmits from this gauge every 15 to 60 minutes. This page bakes in the most recent reading when it is rebuilt, then refreshes live from USGS when you open it. Readings are provisional and subject to revision by USGS.
What is a runnable level on this stretch?
riverlvl deliberately does not publish a runnable range. American Whitewater and the local paddling community maintain the correlations for this reach, and they are the authority. This page gives you the raw inputs — current CFS, gage height, the seasonal median, and the 12-month hydrograph — so you can apply whatever range you trust.
How fast can this gauge come up?
This is a free-flowing gauge, so it rises with rain in the basin. The 12-month chart on this page shows the shape of the past year's rises, which is the best available guide to how flashy this particular reach is.
Where does this data come from?
The flow and gage height come from USGS gauge 01646500, public-domain data from the U.S. Geological Survey. The flood categories, impact statements and forecast come from the National Weather Service's National Water Prediction Service, gauge BRKM2.