USGS Streamgage 11520500
Klamath River near Seiad Valley, CA
Klamath River near Seiad Valley, CA is USGS streamgage 11520500 in California, monitoring river discharge in hydrologic subbasin 18010206. It drains a watershed of about 6,940 square miles. Discharge records at this site go back to 1912. Typical flow runs near 1,294.8 cfs in July and 5,106.3 cfs in April, with the higher of the two arriving in April.
Gauge details
- State
- California
- Drainage area
- 6,940 sq mi
- Gauge elevation
- 1,314 ft
- Subbasin (HUC-8)
- 18010206
- Coordinates
- 41.85374, -123.23227
- USGS site number
- 11520500
- Records begin
- 1912-10-01 (114 years)
Typical flow by month
Long-term daily discharge percentiles from the USGS record (up to 114 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 | 1,805.8 | 3,549.4 | 10,260.6 | |
| February | 1,812.8 | 4,207.9 | 11,339.3 | |
| March | 1,957.4 | 4,684.2 | 11,612.9 | |
| April | 2,210 | 5,106.3 | 10,123 | |
| May | 1,971.6 | 4,230 | 8,718.4 | |
| June | 1,314 | 2,411.3 | 5,880 | |
| July | 933.6 | 1,294.8 | 2,795.8 | |
| August | 889.8 | 1,236.8 | 2,006.5 | |
| September | 1,033 | 1,461 | 2,228 | |
| October | 1,185.5 | 1,713.2 | 3,063.2 | |
| November | 1,309.7 | 2,223 | 4,532.7 | |
| December | 1,491.9 | 2,938.1 | 7,660 |
All values in cubic feet per second (cfs).
Common questions
- When does Klamath River near Seiad Valley, CA normally run highest?
- April, on the long-term record. The median daily flow that month is about 5,106.3 cfs, against 1,236.8 cfs in August, the lowest month. These are historical normals for the date, not a forecast and not today's reading.
- What is a normal flow for Klamath River near Seiad Valley, CA?
- It depends on the month. In January, half of days historically fall near 3,549.4 cfs, with the middle 80% of days between 1,805.8 and 10,260.6 cfs. The month-by-month table on this page gives the full range.
- How long has Klamath River near Seiad Valley, CA been measured?
- Discharge records at USGS site 11520500 begin in 1912, about 114 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 Klamath River near Seiad Valley, CA?
- The gauge sits at 41.85374, -123.23227, in California, in hydrologic subbasin 18010206, at an elevation of about 1,314 feet, draining roughly 6,940 square miles.
- Can I use Klamath River near Seiad Valley, 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.