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 2026-10-13); streamflow classes place each USGS gauge's latest reading against its own day-of-year record.
Health score
51
Moderate
Drought index
179
Moderate
Area in D2+
8.08%
0% exceptional (D4)
Gauges below normal
100%
of 4 reporting
Median flow
64%
p11 of record
Water assets
930
0 springs · 109 wells
USGS gauges (5)
- Bighorn River at bridge, at St. Xavier, MT062878001,720 cfsp9 · much below normal
- Bighorn River at Two Leggins Bridge, near Hardin062884001,780 cfsp11 · below normal
- Bighorn R bl Yellowtail Afterbay Dam nr St. Xavier062870001,590 cfsp12 · below normal
- Bighorn River ab Tullock Cr nr Bighorn MT062945001,830 cfsp21 · below normal
- Big Horn Canal near St. Xavier MT06286490no readingno long-term record
Recent conditions
| Date | DSCI | D2+ % | Gauges low | Flow pct |
|---|---|---|---|---|
| 2026-10-21 | 179 | 8.08 | — | — |
| 2026-10-20 | 179 | 8.08 | 4/4 | p11 |
| 2026-10-19 | 179 | 8.08 | 4/4 | p12 |
| 2026-10-18 | 179 | 8.08 | 4/4 | p12 |
| 2026-10-17 | 179 | 8.08 | 4/4 | p11 |
| 2026-10-16 | 179 | 8.08 | 4/4 | p15 |
| 2026-10-15 | 197 | 21.5 | 4/4 | p20 |
| 2026-10-14 | 197 | 21.5 | 3/4 | p15 |
| 2026-10-13 | 197 | 21.5 | 4/4 | p16 |
| 2026-10-12 | 197 | 21.5 | 4/4 | p18 |
| 2026-10-11 | 197 | 21.5 | 4/4 | p17 |
| 2026-10-10 | 197 | 21.5 | 4/4 | p17 |
| 2026-10-09 | 197 | 21.5 | 4/4 | p16 |
| 2026-10-08 | 222 | 21.5 | 4/4 | p18 |
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