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USGS Gauge 01645704 — Difficult Run above Fox Lake near Fairfax, Virginia
2 cfs.
Open in BirdTrout Get it on the App Store38.88469518, -77.3324293. This gauge on USGS Water Data →
Right now
- 65.3 °F Water temperature
- 2 Cubic ft / second
Live from USGS — the numbers above are current rather than whenever the page was written.
Daily means from USGS. A gap in the line is a gap in the record.
The record at this gauge
| Month | Mean temp | Mean flow |
|---|---|---|
| Jan | — | 7 |
| Feb | — | 6 |
| Mar | — | 6 |
| Apr | — | 6 |
| May | — | 8 |
| Jun | — | 5 |
| Jul | — | 7 |
| Aug | — | 5 |
| Sep | — | 4 |
| Oct | — | 3 |
| Nov | — | 3 |
| Dec | — | 6 |
- 142Highest flow, 2022-05-07
- 1Lowest flow, 2024-11-09
Computed here from the last 5 years of USGS daily values at this gauge — 0 temperature days and 1,825 flow days. These are not USGS-published normals, and a month with fewer than 20 days of record is left blank rather than averaged.
What this gauge predicts
This is one of the gauges this site fits an air-to-water model against, which is how the map colours water that has no gauge on it. July mean 75.36 °F; the fit explains 90% of the variance with a typical error of 1.759 °F.
The water it stands in
Difficult Run.
We hold no coldwater classification for this river, so the page makes no claim about one. The gauge is here because it stands close to water that does carry a designation.
Snapped to NHD reach Difficult Run (10000500089396), 27.5 m away. That join is what lets the app paint this gauge's reading onto the reach it measures.
Other gauges near this one
- S F Little Difficult Run above Mouth Nr Vienna, VA 1.7 mi · USGS 01645762
- The Glade near Howland Drive at Reston, VA 2.8 mi · USGS 0164579522
- Snakeden Branch above Lake Audubon at Reston, VA 3.1 mi · USGS 0164578734
Fly shops nearby
- District Angling12.1 mi · Arlington
- Orvis17.3 mi