Lower Bighorn HUC8 10080015
A 5,082 km² sub-basin of the Missouri region in MT. Drought coverage is from the US Drought Monitor (map of 2026-09-01); streamflow classes place each USGS gauge's latest reading against its own day-of-year record.
Health score
48
Stressed
Drought index
214
Severe
Area in D2+
14.36%
0% exceptional (D4)
Gauges below normal
80%
of 5 reporting
Median flow
67%
p10 of record
Water assets
930
0 springs · 109 wells
USGS gauges (5)
- Bighorn River ab Tullock Cr nr Bighorn MT062945001,690 cfsp10 · much below normal
- Bighorn River at bridge, at St. Xavier, MT062878001,600 cfsp10 · much below normal
- Bighorn R bl Yellowtail Afterbay Dam nr St. Xavier062870001,490 cfsp10 · much below normal
- Bighorn River at Two Leggins Bridge, near Hardin062884001,420 cfsp13 · below normal
- Big Horn Canal near St. Xavier MT06286490399 cfsp77 · above normal
Recent conditions
| Date | DSCI | D2+ % | Gauges low | Flow pct |
|---|---|---|---|---|
| 2026-09-07 | 214 | 14.36 | 4/5 | p10 |
Top water assets
- 69Rotten Grass Creekriver
- 69Rotten Grass Creekriver
- 69Rotten Grass Creekriver
- 69Rotten Grass Creekriver
- 67Woody Creekriver
- 67Bighorn Riverriver
- 67Tullock Creekriver
- 67Rotten Grass Creekriver
- 67Bighorn R Bl Yellowtail Afterbay Dam Nr St. Xavierriver
- 67Bighorn River At Bridge, At St. Xavier, Mtriver