USGS Streamgage 06099500
Marias River near Shelby, MT
Marias River near Shelby, MT is USGS streamgage 06099500 in Montana, monitoring river discharge in hydrologic subbasin 10030203. It drains a watershed of about 2,716 square miles. Discharge records at this site go back to 1902. Typical flow runs near 747.5 cfs in July and 896.9 cfs in April, with the higher of the two arriving in April.
Gauge details
- State
- Montana
- Drainage area
- 2,716 sq mi
- Gauge elevation
- 3,102 ft
- Subbasin (HUC-8)
- 10030203
- Coordinates
- 48.4272, -111.88984
- USGS site number
- 06099500
- Records begin
- 1902-04-01 (124 years)
Typical flow by month
Long-term daily discharge percentiles from the USGS record (up to 124 years of data), averaged within each month. These describe the historical normal range — they are not a forecast and not today's reading.
| Month | Low p10 | Typical p50 | High p90 | Range |
|---|---|---|---|---|
| January | 117.7 | 215.3 | 419.3 | |
| February | 125.3 | 243.5 | 548.4 | |
| March | 194.9 | 393.2 | 1,112.3 | |
| April | 387.9 | 896.9 | 2,000 | |
| May | 1,127 | 2,306.5 | 4,647.7 | |
| June | 920.6 | 2,289 | 5,483 | |
| July | 248.5 | 747.5 | 2,045.8 | |
| August | 120.6 | 296.8 | 698.5 | |
| September | 111 | 256.5 | 570.1 | |
| October | 157 | 305.5 | 684.6 | |
| November | 171.9 | 312.3 | 654.9 | |
| December | 138 | 248.4 | 518.7 |
All values in cubic feet per second (cfs).