USGS Streamgage 11337000
Contra Costa Cn near Oakley, CA
Contra Costa Cn near Oakley, CA is USGS streamgage 11337000 in California, monitoring river discharge in hydrologic subbasin 18040003. Discharge records at this site go back to 1950. Typical flow runs near 181.3 cfs in July and 83.3 cfs in April, with the higher of the two arriving in July.
Gauge details
- State
- California
- Gauge elevation
- 20 ft
- Subbasin (HUC-8)
- 18040003
- Coordinates
- 37.99548, -121.7019
- USGS site number
- 11337000
- Records begin
- 1950-02-01 (76 years)
Typical flow by month
Long-term daily discharge percentiles from the USGS record (up to 52 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 | 21.7 | 59.5 | 128.8 | |
| February | 21.5 | 58 | 145.8 | |
| March | 23.6 | 60.7 | 146.6 | |
| April | 39.9 | 83.3 | 183.6 | |
| May | 41.6 | 116.2 | 214.7 | |
| June | 78.1 | 167 | 235.5 | |
| July | 67.7 | 181.3 | 247.6 | |
| August | 76.8 | 181.3 | 239.9 | |
| September | 65.3 | 145.7 | 216.5 | |
| October | 50.2 | 112.2 | 174.3 | |
| November | 39 | 83.3 | 146.9 | |
| December | 29.7 | 62.1 | 129.8 |
All values in cubic feet per second (cfs).
Common questions
- When does Contra Costa Cn near Oakley, CA normally run highest?
- July, on the long-term record. The median daily flow that month is about 181.3 cfs, against 58 cfs in February, the lowest month. These are historical normals for the date, not a forecast and not today's reading.
- What is a normal flow for Contra Costa Cn near Oakley, CA?
- It depends on the month. In January, half of days historically fall near 59.5 cfs, with the middle 80% of days between 21.7 and 128.8 cfs. The month-by-month table on this page gives the full range.
- How long has Contra Costa Cn near Oakley, CA been measured?
- Discharge records at USGS site 11337000 begin in 1950, about 76 years, covering roughly 55 days of published daily values. The long record is what makes the monthly percentiles on this page meaningful.
- Where is Contra Costa Cn near Oakley, CA?
- The gauge sits at 37.99548, -121.7019, in California, in hydrologic subbasin 18040003, at an elevation of about 20 feet.
- Can I use Contra Costa Cn near Oakley, 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.