Difficult Run Near Great Falls, Va Realtime Data
DIFFICULT RUN NEAR GREAT FALLS, VA
Realtime Data • Report • Conditions
23
Discharge (cfs)
2.9
Gauge Height (ft)
USGS 01646000
Streamflow discharge was last observed at 23 cfs, and a gauge height of 2.87 feet.
With the
% decrease since yesterday,
the streamflow average over the past 10 days is 67 .
Weather today, Tomorrow,
The run is also impacted by the nearby Great Falls Dam, which regulates flow downstream. Seasonally, the flow tends to be highest in the spring due to snowmelt and lower in the summer and fall. Interesting facts about the hydrology of this area include its importance as a source of drinking water for the Washington, DC area and its role in providing habitat for a variety of aquatic species, including the threatened eastern hellbender salamander.
July 13, 2026
| Elevation | 157.0 ft |
| Last Updated | |
| Gage height, ft | 2.87 ft |
| Nitrate plus nitrite, water, in situ, mg/L as N | 0.79 mg/l as N |
| Streamflow, ft³/s | 22.7 ft3/s |
| Specific conductance, water, unfiltered, microsiemens per centimeter at 25°C | 167.0 uS/cm @25C |
| Dissolved oxygen, water, unfiltered, mg/L | 8.0 mg/l |
| Turbidity, water, unfiltered, monochrome near infra-red LED light, 780-900 nm, detection angle 90 ±2.5°, formazin nephelometric units (FNU) | 17.4 FNU |
| pH, water, unfiltered, field, standard units | 7.3 std units |
| Temperature, water, °C | 25.1 deg C |
| Percent of Normal | 91% |
| Year Over Year Average | 25 cfs |
| 24hr Flow Prediction | cfs |
| Maximum Recorded | 8,640 cfs |
| Geolocation | 38.98, -77.25 |
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