About this river
Difficult Run is a 6.7 mile stream near Valley Mill Kayak School in Maryland. Streamflow is measured at the USGS gauge Difficult Run near Great Falls, VA (site 01646000). The National Hydrography Dataset places it at stream order 4. Reach geometry comes from the USGS National Hydrography Dataset.
Typical flow by month
1935 to 2026
Difficult Run typically runs highest in March, at a median 60 cfs, and lowest in September, at 18 cfs. The highest flow on record for any single day is 25,000 cfs, in 1972.
| Month | Typical (cfs) | Usual range (cfs) | Relative level |
|---|---|---|---|
| January | 47 | 31 to 70 | |
| February | 54 | 39 to 78 | |
| March | 60 | 43 to 86 | |
| April | 56 | 41 to 84 | |
| May | 48 | 33 to 75 | |
| June | 37 | 22 to 53 | |
| July | 26 | 16 to 41 | |
| August | 21 | 11 to 35 | |
| September | 18 | 9.4 to 28 | |
| October | 20 | 13 to 32 | |
| November | 28 | 20 to 45 | |
| December | 38 | 27 to 60 |
Typical is the median of each month’s daily median values, and the usual range runs from the median 25th to the median 75th percentile, across about 91 years of record. Statistics published by the US Geological Survey for Difficult Run near Great Falls, VA (site 01646000). Conditions on any given day can fall well outside the usual range. Check the current reading before you go.
Embed this gauge on your site
Paste this snippet anywhere, an outfitter page, a club site, a trip report, to show Difficult Run's live streamflow, water level and 7-day trend. It reads the USGS gauge directly, updates itself, and links back here.
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