USGS Streamgage 11390500
Sacramento River below Wilkins Slough near Grimes, CA
Sacramento River below Wilkins Slough near Grimes, CA is USGS streamgage 11390500 in California, monitoring river discharge in hydrologic subbasin 18020104. It drains a watershed of about 12,915 square miles. Discharge records at this site go back to 1938. Typical flow runs near 7,168.4 cfs in July and 8,898.3 cfs in April, with the higher of the two arriving in April.
Gauge details
- State
- California
- Drainage area
- 12,915 sq mi
- Gauge elevation
- -1 ft
- Subbasin (HUC-8)
- 18020104
- Coordinates
- 39.00987, -121.82466
- USGS site number
- 11390500
- Records begin
- 1938-10-01 (88 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 | 5,793.9 | 12,381.3 | 26,374.2 | |
| February | 5,982.4 | 14,551.7 | 26,944.8 | |
| March | 6,096.8 | 13,606.5 | 26,171 | |
| April | 4,787.7 | 8,898.3 | 23,036.7 | |
| May | 4,650 | 7,365.8 | 17,554.8 | |
| June | 4,582.7 | 6,696.7 | 12,153.7 | |
| July | 4,912.3 | 7,168.4 | 9,791.9 | |
| August | 4,998.7 | 6,972.6 | 9,535.5 | |
| September | 5,129.3 | 6,987 | 9,542.3 | |
| October | 4,227.1 | 5,841 | 8,704.5 | |
| November | 4,177 | 6,290.7 | 13,502.7 | |
| December | 4,671.6 | 8,990 | 23,903.2 |
All values in cubic feet per second (cfs).
Common questions
- When does Sacramento River below Wilkins Slough near Grimes, CA normally run highest?
- February, on the long-term record. The median daily flow that month is about 14,551.7 cfs, against 5,841 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 below Wilkins Slough near Grimes, CA?
- It depends on the month. In January, half of days historically fall near 12,381.3 cfs, with the middle 80% of days between 5,793.9 and 26,374.2 cfs. The month-by-month table on this page gives the full range.
- How long has Sacramento River below Wilkins Slough near Grimes, CA been measured?
- Discharge records at USGS site 11390500 begin in 1938, about 88 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 below Wilkins Slough near Grimes, CA?
- The gauge sits at 39.00987, -121.82466, in California, in hydrologic subbasin 18020104, at an elevation of about -1 feet, draining roughly 12,915 square miles.
- Can I use Sacramento River below Wilkins Slough near Grimes, 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.