USGS Streamgage 11389500
Sacramento River A Colusa, CA
Sacramento River A Colusa, CA is USGS streamgage 11389500 in California, monitoring river discharge in hydrologic subbasin 18020104. It drains a watershed of about 12,090 square miles. Discharge records at this site go back to 1921. Typical flow runs near 8,515.2 cfs in July and 9,167.7 cfs in April, with the higher of the two arriving in April.
Gauge details
- State
- California
- Drainage area
- 12,090 sq mi
- Gauge elevation
- -2 ft
- Subbasin (HUC-8)
- 18020104
- Coordinates
- 39.21403, -122.00022
- USGS site number
- 11389500
- Records begin
- 1921-04-11 (105 years)
Typical flow by month
Long-term daily discharge percentiles from the USGS record (up to 81 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 | 5,549 | 11,821.3 | 37,496.8 | |
| February | 5,644.5 | 13,737.9 | 39,193.1 | |
| March | 6,048.1 | 13,161.3 | 35,645.2 | |
| April | 5,382 | 9,167.7 | 27,803.3 | |
| May | 5,731 | 8,257.4 | 18,706.5 | |
| June | 5,805.7 | 7,900 | 13,256.7 | |
| July | 6,284.8 | 8,515.2 | 11,154.8 | |
| August | 5,954.8 | 8,001.9 | 10,383.5 | |
| September | 5,198 | 6,980.3 | 9,540.7 | |
| October | 4,250.6 | 5,780.6 | 8,641 | |
| November | 4,220.3 | 6,307 | 13,736 | |
| December | 4,660 | 8,691.3 | 30,164.5 |
All values in cubic feet per second (cfs).
Common questions
- When does Sacramento River A Colusa, CA normally run highest?
- February, on the long-term record. The median daily flow that month is about 13,737.9 cfs, against 5,780.6 cfs in October, the lowest month. These are historical normals for the date, not a forecast and not today's reading.
- What is a normal flow for Sacramento River A Colusa, CA?
- It depends on the month. In January, half of days historically fall near 11,821.3 cfs, with the middle 80% of days between 5,549 and 37,496.8 cfs. The month-by-month table on this page gives the full range.
- How long has Sacramento River A Colusa, CA been measured?
- Discharge records at USGS site 11389500 begin in 1921, about 105 years, covering roughly 9,126 days of published daily values. The long record is what makes the monthly percentiles on this page meaningful.
- Where is Sacramento River A Colusa, CA?
- The gauge sits at 39.21403, -122.00022, in California, in hydrologic subbasin 18020104, at an elevation of about -2 feet, draining roughly 12,090 square miles.
- Can I use Sacramento River A Colusa, CA data for flood or safety decisions?
- No. Rivermatics provides estimates, not guarantees, and the readings and forecasts here may be delayed, inaccurate, or wrong. Do not use them for navigation or for any safety, rescue, or emergency decision. Check the National Weather Service and USGS directly, and use your own judgment.