Difficult Run Near Great Falls, VA
USGS Site No: 01646000 • Difficult Run • Fairfax County, VA
Difficult Run Near Great Falls, VA on the Difficult Run is currently at 24 cfs (Normal — 28th percentile for this date) . Gage height: 2.87 ft.
Reading from
Historical Percentile Comparison
Today's discharge compared to the long-term record for June 11 at this station. Percentile rank shows what fraction of historical years had lower flow on this date.
| Percentile | Label | CFS Threshold | Today's Flow |
|---|---|---|---|
| 10th | Very Low threshold | 18 | |
| 25th | Low threshold | 22 | |
| 50th (Median) | Normal (median) | 36 | Today: 24 cfs |
| 75th | High threshold | 49 | |
| 95th | Very High threshold | 274 |
30-Day Hydrograph
Recent discharge plotted against the historical 10th–95th percentile envelope for the same calendar days. Source: USGS daily values + long-term statistics.
30-Day Flow History
| Date | Discharge (CFS) | Gage Ht (ft) |
|---|---|---|
| May 28, 2026 | 34 | — |
| May 27, 2026 | 41 | — |
| May 26, 2026 | 53 | — |
| May 25, 2026 | 87 | — |
| May 24, 2026 | 692 | — |
| May 23, 2026 | 170 | — |
| May 22, 2026 | 84 | — |
| May 21, 2026 | 64 | — |
| May 20, 2026 | 13 | — |
| May 19, 2026 | 12 | — |
| May 18, 2026 | 13 | — |
| May 17, 2026 | 13 | — |
| May 16, 2026 | 15 | — |
| May 15, 2026 | 20 | — |
| Apr 21, 2026 | 18 | — |
| Apr 20, 2026 | 21 | — |
| Apr 19, 2026 | 19 | — |
| Apr 18, 2026 | 18 | — |
| Apr 17, 2026 | 19 | — |
| Apr 16, 2026 | 21 | — |
| Apr 15, 2026 | 22 | — |
| Apr 14, 2026 | 22 | — |
| Apr 13, 2026 | 22 | — |
| Apr 12, 2026 | 22 | — |
| Apr 11, 2026 | 24 | — |
| Apr 10, 2026 | 24 | — |
| Apr 9, 2026 | 24 | — |
| Apr 8, 2026 | 25 | — |
| Apr 7, 2026 | 30 | — |
| Apr 6, 2026 | 54 | — |
Station Information
- USGS Site No
- 01646000
- State
- VA
- County
- Fairfax County
- Coordinates
- 38.9759, -77.2458
- Drainage Area
- 58 mi²
- Datum (ft)
- 150.9
- HUC Code
- 02070008
Flood Stage Thresholds
- Action Stage
- 9.0 ft
- Flood Stage
- 11.0 ft
- Moderate Flood
- 13.0 ft
- Major Flood
- 20.0 ft
Currently 8.13 ft below flood stage.
Recent Extremes
- Max discharge
-
724 cfsMay 13, 2025
- Min discharge
-
4 cfsOct 6, 2025
- Days at flood stage
- 0
Computed from the local daily-values archive.
Nearby Gauges
-
Fourmile Run at Alexandria, VALow12.6 mi · 4 cfs
-
Potomac River at Point Of Rocks, MDVery High26.0 mi · 34,600 cfs
-
Patapsco River Near Catonsville, MDNormal32.1 mi · 123 cfs
-
Patapsco River Near Elkridge, MDNormal33.0 mi · 132 cfs
-
Patapsco River at Hollofield, MDNormal33.5 mi · 92 cfs