USGS Streamgage 06019500
Ruby River above reservoir near Alder, MT
Ruby River above reservoir near Alder, MT is USGS streamgage 06019500 in Montana, monitoring river discharge in hydrologic subbasin 10020003. It drains a watershed of about 534 square miles. Discharge records at this site go back to 1938. Typical flow runs near 173.7 cfs in July and 148.3 cfs in April, with the higher of the two arriving in July.
Gauge details
- State
- Montana
- Drainage area
- 534 sq mi
- Gauge elevation
- 5,412 ft
- Subbasin (HUC-8)
- 10020003
- Coordinates
- 45.19232, -112.14282
- USGS site number
- 06019500
- Records begin
- 1938-05-01 (88 years)
Typical flow by month
Long-term daily discharge percentiles from the USGS record (up to 87 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 | 85 | 101.4 | 121.1 | |
| February | 84.9 | 100.2 | 118.4 | |
| March | 88.7 | 104.6 | 136.2 | |
| April | 104.6 | 148.3 | 247.5 | |
| May | 199.3 | 365.7 | 717.9 | |
| June | 190.2 | 402.3 | 858.2 | |
| July | 95.2 | 173.7 | 321.6 | |
| August | 77 | 111.7 | 176.8 | |
| September | 84.7 | 111.1 | 152.7 | |
| October | 96.5 | 124.3 | 157.6 | |
| November | 101.4 | 118.9 | 146.1 | |
| December | 90.5 | 107.6 | 130.1 |
All values in cubic feet per second (cfs).